Fire crews in Kaikōura are bracing for more severe gales as they battle multiple blazes that destroyed five homes and several other buildings.
Incident Controller Dave Key says 11 crews, including heavy machinery and dangerous tree fellers, are working across a large area of Kaikoura Flats to strengthen the containment lines around each of the fires before the wind is due to pick up this afternoon.
There have also been two helicopters assisting with ground crews.
"There's a number of dangerous trees ... they're burning from the inside out so that's a priority for us and really strengthening our containment lines while we've got this small weather window before the wind picks up this afternoon and more again tomorrow," Key said.
The fires, fanned by fierce winds destroyed 14 buildings, including the five houses, but firefighters were able to save another five homes.
About 20 people were evacuated.
While the fires continue to burn, there was some good news for travellers this morning - State Highway 1, which was closed overnight between Ward and Kaikōura, has reopened.
"We've got a lull in the weather today that's allowing us to fly our helicopters and extinguish that fire," Assistant National Commander Ken Cooper said.
He said crews yesterday responded to six vegetation fires, and it was three of those which had damaged property.
"There are a number of fires that have been lit in the open over the last number of days that weren't properly extinguished and the wind obviously fanned those and caused those fires to reignite," Cooper said.
One was driftwood on a beach being used as a bonfire, another was a shelterbelt.
He said it wasn't clear if any of the lit fires were the ones that had damaged the structures and homes.
There was now a race to put the fires out ahead of more severe weather forecast for Thursday.
"What we're really trying to stress going forward is really imperative - that we get across to everyone is that we have a significant event coming in from midnight," he said.
RNZ reporter Keiller McDuff, who is in Kaikōura, earlier said it was not yet known how the fires started.
However, once they started the high winds created "a bit of a disaster" in terms of spreading dozens of fires.
"The fire ground is incredibly dispersed."
It covered a wide swathe of the northern part of town and jumped State Highway 1.
In a social media post, the Kaikōura Volunteer Fire Brigade said it sent its thoughts to those who lost their homes yesterday.
"We tried as hard as we could but just couldn’t save them all."
There were also fires in the southern part of Marlborough and some fire crews on their way to Kaikōura had to turn back to deal with those.
Winds also allowed the fires there to spread.
Assistant National Commander Ken Cooper said the wind was expected to drop today and then pick up again tonight, and he wanted the fires out before then.
He says they are now looking at what is going to be needed when gale-force winds with high temperatures hit the east coast of both main islands from early tomorrow.
At the height of the response, about 50 appliances attended with about 120 personnel working to extinguish the flames.
About 30 appliances stayed overnight, the crews mainly protecting other structures.
MetService says it's possible some of the warnings for damaging gales and heavy rain for central and southern parts of the country may be upgraded to red.
Severe weather alerts are in place for almost all of the South Island, and MetService earlier this week said Thursday would be a "big day" of weather.
State Highway 1 near Kaikōura was closed overnight because of the fires, but reopened about 8.25am. However, other highways remain closed.
Fallen trees are blocking Inland Route 70 which is closed from Peketā south of Kaikōura to Waiau.
Flooding has also shut the Lewis Pass (SH7).
MainPower's outage map shows power is out for hundreds of homes spread across several areas.
It says teams are working to restore electricity as safely and as fast as possible.
It's also warning of what it says is a significant weather event due to strike tomorrow.
Canterbury's Civil Defence Emergency Management says the forecast is for stronger wind and higher temperatures across a broader area.
It's urging people to use today to prepare, and consider how the wind may affect them and their property.
Meanwhile, some highways are closed in the North Island after strong winds and heavy rain caused major disruptions, and power remains out to thousands of people in Wairarapa.
Four vegetation fires continue to burn in Pōrongahau in Hawke's Bay.
Firefighters have been monitoring the fires overnight - and operations were expected to resume at first-light.
Around 50 to 60 firefighters are expected back today.
