Earthquake highlights NZ's road vulnerability

The Kaikoura earthquake, which caused slips that damaged roads and stranded whole towns, has highlighted New Zealand's road vulnerability. Photo / NZME.

New Zealand can no longer be dependent on single road access, a logistics expert says.

Massey University logistics and supply chain management lecturer Jersey Seipel said Monday's 7.8 magnitude earthquake demonstrated how vulnerable parts of the country are after slips on State Highway 1 and damaged railway lines cut off whole towns.

"One of the main lessons to be learned from the disaster is to decrease our vulnerability with regard to single roads leading in or out of a region. This applies to Wellington even more so," Seipel said.

"Alternative routes need to be developed; we simply can no longer rely on a single road as the sole means of access."

Seipel said the main objective now was to re-open the state highway as quickly as possible, while strengthening alternative routes.

Road trips between the top of the South Island and regions further south are now likely to take longer, especially while the railway is out of action, Seipel added.

"Higher freight costs, as well as traffic congestion, are likely as well."

The NZ Transport Agency and Civil Defence are working to reopen and reroute highways and roads in the earthquake-stricken region.

Highways manager Neil Walker said work is continuing to restore access to communities cut off by the damage, and to establish safe and reliable alternative routes.

Crews are working on the Kaikoura Emergency Access Road, Inland Route 70 between Culverden and Kaikoura, clearing slips and assessing the road and structures for damage. The road is under the strict control of Civil Defence Canterbury.

"This is due to the dangerous conditions, and the road is only being used to deliver supplies to Kaikoura."

There is no public access because of the unsafe and challenging conditions, Walker said.

The alternative state highway route from Picton to Christchurch, via Murchison and the Lewis Pass has been open since late Monday afternoon.

"This will likely be the main state highway route from Christchurch to Picton for several months, given the amount of work required to clear the large slips, which have closed SH1."

Controlled access for residents and essential services has also been restored on SH1 south from Seddon to Okiwi Bay, and north from Cheviot to Goose Bay.

"It's important to note that these sections of SH1 are only accessible to local residents or essential services. All other traffic must use the alternate route via the Lewis Pass."

With the closure of SH1, Walker said the Lewis Pass route will be carrying higher volumes of traffic, and people are urged to allow extra time for their journey.

"People should allow an additional 90 minutes to two hours for the journey between Christchurch and Picton on the Lewis Pass route."

The average journey between Christchurch and Picton is expected to take 7 1/2 hours.

Fuel, food and toilet stops are available at Culverden, Springs Junction, Murchison and St Arnaud.

"With continuing aftershocks contributing to the risk of further slips and rockfalls in several parts of the South Island, people are urged to drive with extra caution and comply with all temporary speed restrictions."

Meanwhile, 24-hour highway access to Hanmer Springs from SH7 via SH7A has been restored, following assessments showing a reduced risk of further rockfalls.