Tasmanian fire authorities have rejected claims they turned down an offer from the ADF for assistance fighting bushfires in the World Heritage Area.

Key points: TFS chief officer rejects claims he rejected ADF offer of assistance during bushfire efforts

TFS chief officer rejects claims he rejected ADF offer of assistance during bushfire efforts Greens senator questioned emergency management director general over TFS discussions

Greens senator questioned emergency management director general over TFS discussions Emergency Management Australia boss says states could apply for ADF help but it was not requested

There are still 73 bushfires burning around Tasmania, 26 remain out of control and most are in remote areas.

Emergency Management Australia, a body in the Attorney-General's portfolio, faced scrutiny of the Commonwealth response during Senate estimates last night.

Under questioning from Greens senator Nick McKim about resourcing, the organisation's director-general Mark Crossweller said there was discussion about sending in the defence force to assist.

"The chief [fire] officer [Gavin Freeman] rang me and said no, it was inappropriate to do so," he said.

"The Australian Defence Force has been clear in pre-season briefs that they're not skilled for arduous, direct firefighting,"

"Has the chief [fire] officer in Tasmania requested assistance?" Senator McKim asked Mr Crossweller.

Mr Crossweller replied: "No he hasn't, we what we have been able to do for him is coordinate the interstate response from the rest of Australia."

"He was more interested in firefighting resources, direct frontline resources."

Mr Freeman released a statement claiming assertions he had "refused assistance offers from the ADF" were incorrect.

"I would like to make it very clear that at no time has there been an offer of assistance from the ADF; that's not the way it works," he said.

"Tasmania has to actually request the resources."

He said the ADF did not have firefighting capability and there was "limited scope" for the ADF to assist.

Senator McKim also asked Mr Crossweller about what type of help may be requested of the Commonwealth.

"In a situation like this, does a State Government request general assistance or do they put in requests for certain types of assistance?"

Mr Crossweller said states could apply for "physical or non-physical assistance" from the Commonwealth.

"If that is the case, that hasn't been the case at this stage for Tasmania, if that would be the case then the COMDIS [Commonwealth Disaster] plan would be activated," he said.

"It hasn't happened because they haven't required it.

"The state and territory resource that's been supplied by state and territories obviously has been sufficient and there's nothing that the Commonwealth could offer."

Significant numbers of interstate and NZ crews deployed

Crews from around Australia and New Zealand have been deployed to Tasmania to assist with firefighting efforts.

A team of Remote Area Firefighters is airlifted into a remote Tasmanian forest near a large bushfire. ( ABC News: Linda Hunt )

Mr Crossweller told the hearing one-third of New South Wales' Remote Area Teams, or RATS, had been mobilised.

"I know that New South Wales have supplied on a rotating basis in excess of 100 of those firefighters, New Zealand I think around 50," he said.

"It's probably the single biggest mobilisation of firefighting resources to Tasmania that I'm aware of in 30 years in the industry."

Senator McKim pushed Mr Crossweller on the response to fires burning in the state's wilderness World Heritage Area.

"With wilderness fires in particular, you want to minimise the damage caused by them, ideally you would hit them as hard as you can as early as you can," he said.

"Get them while they are still one, five, 10, 20-hectare fires, before they turn into the 30,000-hectare monsters we have burning in the World Heritage Area."

Mr Crossweller agreed, but said safety was a priority.

"Over the course of my career, I've seen many firefighters perish in similar circumstance where decisions were made to insert early on the basis of keeping fires small," he said.

"But the conditions were such that those fires rapidly escalated and caused entrapment and killed firefighters."