Roger Sutton - the rangy "big picture guy" the Government has appointed Christchurch earthquake czar - says once rebuilding speeds up it will be thundering along at five to 10 times the city's normal rate.
Given that Christchurch is roughly 10 per cent of the New Zealand economy, the business upside is obvious.
Problem is, unlike other natural disasters such as floods and hurricanes where repair work starts once water recedes and winds drop to normal, the "seismic event" is still happening, making it difficult to pinpoint when the major infrastructural work can start.
Sutton says this is a "genuine concern".
The boss of the Canterbury Earthquake Authority (CERA) says there will be about five years' work repairing $2.5 billion of damaged infrastructure.
An alliance has been formed to drive repairs to lifelines including water, sewage and the roads. There have been a few teething problems. But Sutton says, "there is a real feeling we are in this together - a crisis brings out the best in people."
Fletcher Building's infrastructure chief executive Mark Binns agrees the biggest challenge is simply getting moving. "The aftershocks haven't slowed down like most earthquake patterns. This has caused disruption. We have had to do a lot of emergency repairs. Hopefully the shocks are slowing down."
Fletchers is managing the biggest NZ job in its 101-year history as Earthquake Commission project director organising an massive repair job to 60,000 Christchurch homes and land. This covers damage up to a $100,000 cut-off point. "It's just a huge project and the logistics are a big challenge."
The pressure will come on as private insurance work over the $100,000 EQC cap kicks in.
Right now it is unclear when the major part of the private insurance work - commercial buildings and damage exceeding $100,000 in the residential sector - will start. Insurers and reinsurers are still wrangling over boundary issues including to what standard houses should be rebuilt.
Fletchers' gap analysis indicates there will be a major labour shortfall of some 3000-12,000 people. "It is going to be necessary to bring in foreign workers," says Binns. "It's an imprecise science - others have come up with larger numbers. The skills shortage is not a problem now but it is one we are going to face sometime in the rebuild programme."
The infrastructure challenge is immense. More than 200km of roads are to be rebuilt and more than 800km of pipes repaired or replaced. Manholes and pumping stations need extensive work. Bridges, retaining walls and riverbanks need fixing, along with kilometres of curbing, footpaths and roadside berms. Traffic lights, traffic islands, barriers, light stands, parks, reserves and outdoor amenities will have to be repaired.
Binns said the scope of the building demolition phase was also vast. "Grand Chancellor (hotel) is the first of many hundreds, perhaps even a thousand demolitions."
Then, a new phase of reconstruction will start, which will demand the resolution at each site of geotechnical problems, building code issues, planning, insurance claims, economic feasibility and design demands.
Fletcher is also involved in the alliance which is fixing the city's infrastructure - roads, services and a devastated CBD. Other alliance members are CityCare, MacDow, Fulton Hogan and Downer. Each has a 20 per cent share. The Christchurch City Council and CERA are also involved.
The size of the project has not yet been quantified from Fletcher's point of view. However, Binns estimates it could be in the $2.5 billion range.
"Caution needs to be applied in placing reliance on estimates," he warns.
"Even the timing of the overall programming was uncertain, affected not just by the size and number of aftershocks but also the average size of each job, resources in place to complete work, productivity rates and EQC settlement rules."
Once rebuilding starts, he predicts fierce competition among contractors not just for skilled labour but also accommodation. There will inflationary pressure as the cost of materials and labour rises, and the "start-stop implications of after-shocks".
Infometrics forecasts the peak level of activity will occur in 2014 and 2015. It says by this stage, funding and insurance issues will have been resolved, design and planning questions will have been answered and supply chains and labour resources will be working efficiently. At its peak, work associated with the quakes could add about $2 billion to annual work put in place across the three construction sub-sectors.
ANZ's David Green says it is important for the economy that New Zealand makes the investment upfront "so we can start realising the benefit".
"Cabinet can't do it all on its own and Christchurch has created even further challenges, so there are increased opportunities for the private sector to play a role to deliver infrastructure."
Forsyth Barr's Rob Mercer estimates Fletcher will make $250 million to $376 million from its Christchurch work between 2012 and 2019, assuming the cost of rebuilding ranges from $20 billion to $30 billion and that Fletcher scores 20 per cent share of the work.
But Binns has told analysts that Fletcher subsidiaries are not in a favoured position. "Supply is fully contestable. Contractors maintain their own links to the supply base."
The alliance concept emerged after the February 22 earthquake.
Binns said stakeholders wanted a procurement model for the infrastructure rebuild that is faster, delivers better value for money, manages standards and resources across the city and provides resilience for future quakes.
There have been 20,309 emergency house repairs and work on a further 2356 houses is under way. "Priority is given to emergency work - repairs needed urgently to ensure that homes are safe, secure, and sanitary and weather tight," Fletcher says.
Fletcher Construction is not carrying out the repair or building work itself. This is being done by independent contractors who have completed the accreditation process.
Local trades people and businesses get first priority for accreditation.
Many Christchurch people say they have not been visited and have received no help while others have complained about poor work and massive differences between repair estimates. But Fletcher says weathertightness or other habitability issues take priority.
Overseeing the earthquake recovery is Cabinet Minister Gerry Brownlee. He has to ensure that CERA, the EQC, private insurers, local authorities and the major residential project office work in tandem together.
It will be some months, if not years, before the final costs of the Canterbury earthquake are established. The Treasury's economic forecasts assumed $15 billion worth of damage across residential properties and contents, commercial buildings and assets, and infrastructure.
International reinsurers estimate the total could go higher as affected properties are either repaired or replaced, remedial work is done to strengthen soil structures and damaged "lifelines" are replaced.
New Zealand is well served by its natural disaster insurance scheme.
The Department of Building and Housing is incorporating the lessons from the Canterbury earthquake - in particular the effects of soil liquefaction on buildings - into general guidance for application elsewhere. Environmental engineering consultants Tonkin and Taylor are assessing land damage throughout the Canterbury region, and identifying how best to repair residential land damaged by liquefaction or lateral movement.
Coffey Geotechnics' Nick Harwood says the key challenges are the huge scale of damage and complexity of the remedial works, ensuring continuity of logistics, determining appropriate remediation measures and ensuring there are sufficient resources.
In the mid-1990s, Canterbury set up a multi-disciplinary approach to mitigate the vulnerability of lifelines to natural hazards. These lifeline utilities include the electricity networks, telecommunications, broadcasting, petroleum distributors, gas suppliers, water supply, wastewater, storm water and transportation.
Canterbury's earthquakes have been a wake-up call for the capital. A movement on the faultline bisecting Wellington is likely to result in an earthquake of approximately 7.5 with surface rupture of more than 50 km.
The latest Government National Infrastructure Plan outlines a three-year action plan to build resilience into key infrastructure. The Christchurch experience demonstrates why that is necessary.
The scorecard so far
* Hubs established: 18 in Christchurch, Selwyn, Waimakariri, Hurunui, Ashburton.
* Contracting firms: 741 accredited, ahead of plan
* People: 5900+ contractors, trades people and others inducted.
* Emergency repairs: 20,309 completed and 2356 in progress
* Winter heat: 8860 jobs completed, 6619 heat pumps and 2241 solid fuel burners.
* Full-scope repairs: 9276 completed or in progress.
* Payments: About $80 million paid to contractors.
* Currently paying $400 million annually and rising.
* Source: Earthquake Recovery, Fletcher Construction/Earthquake Commission project, as at July 15