A helicopter involved in fighting the Nelson fires has crashed.

A Fire and Emergency NZ spokesman said the chopper when down at 2.49pm while working in the Pigeon Valley area on the Tasman fires.

It was carrying a monsoon bucket at the time. There was only the pilot on board.

Civil Defence Controller Roger Ball said the pilot was out of the helicopter and receiving treatment for non-life threatening injuries.

The FENZ spokesman said "all aircraft operations have been suspended".

Weather was reportedly fine at the time, with light north to northwesterlies.

The Tasman fires started nearly two weeks ago after a spark from a tractor ignited tinder dry grass and scrub on Pigeon Valley Hill, about 30km south of Nelson.

The fire, which has covered more than 2000 hectares, has claimed one cottage and seen up to 3000 residents evacuated. Up to 150 firefighters and dozens of helicopters have been battling the blaze.

While the flames are largely out now there are still lots of hotspots underground which can flare up quickly.

More to come