Rain relief on the way for Canterbury

Farmers and landowners of "tinderbox dry" land on the outskirts of Christchurch should receive a reprieve this week as temperatures drop and rain is due to sweep in tomorrow.

Firefighters over the weekend kept a watchful eye on the scene of last week's devastating fires which gutted two homes, destroyed many other farm buildings and commercial properties, and killed 18,000 laying chickens.

There were several flare-ups in the area overnight, but they were quickly dampened down by firefighters who remained on high alert and have been on continuous rolling shifts since Thursday.

Helicopters with thermal imaging equipment surveyed the area between Rolleston and Templeton at 6am today.

They have identified areas using GPS technology for four ground crews and appliances to move in and dampen down.

Wilson Brown, principal rural fire officer for the Selwyn District Council, said they will remain vigilant, and he pleaded with the public to do the same.

He welcomed news from the MetService that rain was on its way.

MetService meteorologist Daniel Corbett says Cantabs have been considering "doing a rain dance" after the searing temperatures and bone dry fortnight.

But the forecast over the next three days will be welcomed by the whole region, he said.

"The best news is the strong, dry, warm nor'westers have eased," Mr Corbett said.

A low front coming in to the west coast of central New Zealand later today will bring an onshore wind flow and rain for parts of Canterbury tomorrow.

Today it is cloudy, with south-west winds and a high of 22C, and tomorrow just 16C and rain.

"Rain will obviously improve conditions because it's just been so tinderbox dry down there," Mr Corbett said.

"You can almost imagine people jumping up and down saying, 'Yay, it's raining'."

The most important weather indicator that firefighters will be looking at, he said, was the dew point, which is the point where the air reaches saturation.

"That has been very low, and hence the air has been very dry. The onshore flow will moisten the air, and firefighters will say it will improve conditions," Mr Corbett said.