Centrelink is investigating more than 100 potential cases of people wrongly claiming bushfire grants after Tasmania's January fires.

The investigation comes as concerns surface about people taking advantage of victims and charities.

Three days after fires destroyed homes and farms in Tasmania, the Prime Minister visited the state to announce Commonwealth assistance.

So far the Federal Government has paid out $7.5 million to more than 6,000 people.

Federal Community Services Minister Julie Collins says Centrelink believes 180 claims are suspicious.

"Centrelink have done a check on it, we make it easy for people to claim at the time, but around 180 or 2.5 per cent of claims need further investigation," the minister said.

She believes some cases could simply be mistaken payments.

"Perhaps Centrelink needs more information. If there is a case where it has been fraudulently claimed that will then be referred to the DPP."

Consumer Affiairs and Fair Trading has received reports of profiteering.

Spokeswoman Jennifer Lee says one person was trying to charge fire victims for tree removal.

"We have had some unconfirmed reports of people giving the impression that they're volunteers, doing work and then trying to charge the householder for that work."

As the recovery gathers pace, Ms Lee is warning bushfire victims to be on the lookout for shonky builders.

"They are very pushy about getting money upfront and in some places they've been known to drive people to ATMS so that they can get the cash to pay for the work," she said.

Charities believe conmen are in the minority.

Foodbank Tasmania's Ed Gauden says two months after the fires, many victims still need food and basic essentials.

"There are people that need that help genuinely, there are also people that are taking advantage of it, sad to say,"

"But I, from Foodbank perspective, am not the policeman. If people say they're in need we will try to assist."

Foodbank says although its resources are stretched, it will continue giving food to fire victims, as well as providing food hampers to charities.