First vehicles roll across Waiho River's new bridge

The first vehicles have rolled across the Waiho River's rebuilt  bridge, just 17 days after the original was destroyed in a storm.

Westland District Mayor Bruce Smith was there on the day it was spectacularly washed away.

"I was standing on the bridge and there was rocks and things hitting it, it was shuddering away," he told Newshub on Saturday, at the official opening of the new bridge on State Highway 6.

"I wandered off the bridge and within a very short period of time, got a text that said 'the bloody bridge has gone'. I thought, what bridge? Come down and had a look, and goodness me."

He estimates the local region lost hundreds of thousands of dollars in income, as tourists cancelled their trips and businesses struggled.

"April is generally a time when you've had a pretty good January, February - April's the cream. No cream this year, boys. It stopped.

"The café in Hokitika where I get my coffee... I had to start queueing a year or so ago. I didn't have to queue the last two weeks."

He was horrified at the thought Franz Josef could be cut off for months.

"To think that the New Zealand Transport Agency, the military, all of the contractors have turned this around in 17 days? It's unbelievable."

NZTA spokesperson Jim Harland said it would have taken a long time and cost a lot of money to build the same kind of bridge that was destroyed, so they opted for a Bailey bridge instead.

"This bridge was built with a very tough river in mind, and it was a Bailey bridge for a very good reason - if we lost spans, we could actually very quickly rebuild it."

Bailey bridges, invented by the British military during World War II, are built from pre-fabricated sections of lattice steel.

There is still work to be done on the new crossing, including asphalting and adding a pedestrian walkway. It currently has a wooden surface.

"Brilliant, isn't it?" said Smith. "Isn't it great we're open for business?"