Twelve rural firefighters from New Zealand will head across the ditch on Wednesday to help battle bushfires in Tasmania.

Authorities made a formal request on Monday evening for help in bringing fires in remote areas of the state under control, says NZ National Rural Fire Officer Murray Dudfield.

They asked for people with experience fighting fires in tall timber, remote and high country areas.

Two crews of six, one group made up of Department of Conservation staff from Northland, and the other of forestry workers from the Nelson region, will fly out on Wednesday afternoon.

"This team will use equipment provided by the local agencies and are likely to be deployed for at least two weeks," Mr Dudfield said.

More than 100 properties have been destroyed by fire in Tasmania since last week.

No deaths from the fires have been reported but emergency services crews are conducting property-to-property searches for human remains.

Mr Dudfield told AAP at this stage, no other requests have been made from Australia for assistance.

New South Wales is facing some of the worst fire conditions in the state's history.

More than 20 uncontained fires are burning across the state and a total fire ban is in place.

"We work very closely with our Australian counterparts and should they have a need in New South Wales, they only have to ask and we can consider their request," Mr Dudfield said.

Over the past decade, New Zealand firefighters have been deployed several times to assist their Australian counterparts fight bushfires.

The largest contingent was sent in 2009 when 110 rural firefighters were deployed to Victoria.