New Zealand to send 20 more firefighters to help battle deadly NSW bushfires

New Zealand is sending more firefighters to help battle the deadly fires in New South Wales, on top of the crew that is already across the ditch.

A 21-strong crew is heading across the ditch to Queensland, where wild fires have been raging for the past nine weeks.

As of yesterday, there were 50 active bushfires in Queensland where a state of fire emergency has been declared.

"Fighting fires of this magnitude is a hugely demanding task and we’re happy to provide support to our Australian colleagues," said Paul Turner Fire and Emergency New Zealand.

"They’re tough firefighting conditions over there at the moment. The hot, very dry and windy conditions are causing extreme wildfire behaviour,” said Mr Turner.

A week-long state of emergency has been declared in NSW and hundreds of schools around the state are closed today.

A catastrophic fire danger rating - the highest possible level - is in place for the Greater Sydney, Greater Hunter and Illawarra Shoalhaven areas.

There is an extreme fire danger rating - the second highest - in place for the North Coast, Southern Ranges, Central Ranges, New England, Northern Slopes and North Western areas.

Temperatures are expected to reach the high 30s in parts with winds gusting up to 80 kilometres per hour.

Fires in NSW since Friday have claimed the lives of three people and destroyed at least 150 homes.