"Time-sensitive import cargoes are likely to be handled through the Ports of Auckland due to vessel scheduling and rotations."
Mr Cowie said more logs were being delivered by rail from Whanganui, Palmerston North and Masterton.
"A number of log exporters have also indicated Napier Port should gear itself for significant increased volumes."
He said Napier could handle any additional volume of containerised or bulk cargoes "with ease" even during the peak apple and squash season between March and May.
"We will do everything possible to minimise the impact of this devastating event on the importers and exporters of the Central North Island. We can only imagine the difficulties that some businesses are facing."
Customs broker, shipping agent and GoGroup chief executive Murray Painter said if Wellington was closed for business then Napier was the next logical port, followed by New Plymouth.
"The decision lies with the shipping company rather than the shipper," he said.
"Napier may have to go 24/7, which would be nice for them."
Many buildings at Wellington port remain off-limits - including Statistics House, which is closed to its 500 staff.
ANZ chief economist Cameron Bagrie said regions outside Wellington may benefit if a lack of confidence in its CBD resulted in a de-centralisation of the civil service.
"It is going to provide economic upswing for some regions around New Zealand if some activities start to get farmed out."
Mr Bagrie said he believed the consequences of the latest earthquakes, particularly for Wellington and more broadly for New Zealand, were a lot more pronounced than currently disclosed.
"As we speak you are seeing more and more news of buildings that are under stress and I suspect, when push comes to shove, are not going to make it," he said.
People would be reluctant to work in buildings below the building code for seismic events. Rising insurance costs would cause "a massive gap" in commercial real estate depending on seismic ratings, Mr Bagrie said.
South Island road repairs would cost many billions of dollars "but the good news is the Government has a huge balance sheet to absorb some of the associated costs".
"There is going to be no shortage of building work for the next five to 10 years - the pipeline is that large - but the biggest issue for the construction sector to manage will be the availability of labour. That is going to make us increasingly reliable on migration."
Other good news was the national economy was looking "pretty damn good", unlike in 2011 when the Christchurch earthquakes put a post-GFC New Zealand economy "back on its heels".
