Firefighters at scene of major scrub fire in Lee Valley in Tasman

Helicopters fighting the Lee Valley fire are back in the air after being grounded due to a drone, Fire and Emergency says.

Six were stood down due to a drone sighting in the area and a seventh helicopter was also stood down before it reached the scene of the fire.

The drone has been located and is no longer flying.

Fire and Emergency Incident Controller Steve Trigg said drones were a safety risk to aerial firefighting, as a mid-air collision with a drone could have fatal consequences.

"The drone sighting has completely impacted helicopter operations. Firefighting efforts are on hold until the safety of air operations can be assured," Trigg said earlier.

The fire is burning over about 5 hectares of a pine forestry block and is not yet contained.

The helicopters have now been stood down for the night and crews will be patrolling the area overnight, before ramping up firefighting activites again in the morning.

Fenz Nelson Marlborough district commander Grant Haywood says about 70 firefighters have been working on the ground to contain the fire.

Firefighters are unable to continue the firefight using ground attack because the terrain is too steep and dangerous.

Meanwhile, 11 properties in the Lee Valley area have been evacuated as firefighters deal with three blazes in some vegetation.

Fire and Emergency has nine crews at the scene of the fire in the Tasman District.

Before the drone incident, they were being supported by helicopters with monsoon buckets.

Eleven houses on River Terrace between the Lee Valley Bridge over the Wairoa River and Mead Road have been evacuated by police.

Nelson-Tasman Civil Defence has opened a civil defence centre for evacuees at the Wanderers' Clubrooms on Lord Rutherford Drive.

Further information on that support is available by calling 03 543 8400.

The separate areas of fire were earlier spreading uphill into a pine plantation, Fire and Emergency says.

Five helicopters are supporting ground crews.

As at 5.30pm the fire was estimated to have covered about three hectares and was not yet contained.

An RNZ reporter near the scene of the fire said it was not a densely populated area.

There was a one-way road up into the valley and police were working there to organise the evacuations.

She could see a plume of smoke up the valley and hear the helicopters working.

She had seen forestry utes and a truck with "a massive digger on the back" heading towards the fire scene to help out.

The reporter said there had been a hot spell in the region recently and there was very little wind from her vantage point observing the fire.

"It's fair to say it's hot and it's pretty dry."

Emergency services were alerted to the fire just before 4pm.

Police also had to help earlier with evacuating swimmers from local swimming spots.

The road is closed at the intersection of Lee Valley Road and Wairoa Valley Road.

People in the area are being asked to avoid non-essential travel, particularly on Paton Road.

FENZ says traffic congestion is delaying some fire trucks from reaching the fire.

Road closures are in place.

Nelson Tasman Civil Defence has also appealed to people to stay away from the area.

"We want to make sure our emergency services can do their job without having to worry about people trying to see what is going on," it says in a social media post.

Meanwhile, Hurunui's mayor Marie Black says firefighters across the Canterbury region are feeling the stress of being called out to one fire after another as the relentless hot weather continues.

A blaze near the Waipara River on Waitangi Day closed State Highway 1, while firefighters from 15 brigades worked to bring it under control.

Black says there does not appear to be any relief in the immediate forecast, with hot weather set to continue in coming months.

She says residents of North Canterbury are used to having a heightened awareness for fire at this time of year, but the repeat events are having an impact on the community.