Tasmanian foster carers are taking in up to seven children a night because of a spike in demand which is stretching a system already under strain.

An extra 250 children entered the system last financial year.

The Foster and Kinship Carers Association Tasmania (FKAT) said there was a desperate need for more carers.

"The market's pretty saturated and then you've got an additional 252 children in one year and then that just creates a lot of stresses on the system," said chief executive Kim Backhouse.

"At the moment we do not have enough carers in the state to actually look after the children coming into the out-of-home care system.

"The carers in the system take additional children so instead of two to three children, some homes might have five, six, seven children a night because of that desperate need."

The concerns come after an ABC Four Corners investigation aired allegations private provider Safe Pathways charged taxpayers hundreds of thousands of dollars a year but did not provide adequate care.

Former staff spoke out, saying they were not trained and the provider failed in its duty of care.

The program highlighted concerns about a 12-year-old boy who did not receive basic essentials, according to a former carer.

The Tasmanian Government defended its handling of the allegations and said the child in question was no longer in the care of Safe Pathways.

It said checks had been made on other children, who were found to be safe.

Human Services Minister Jaquie Petrusma said the organisation had been under investigation since October.

"The department has been keeping a close watch on Safe Pathways to ensure those children are being given the most appropriate care," she told told 936 ABC Radio.

The Minister would not say what the consequences would be if the claims were found to be true.

"There's a raft of consequences that need to be looked at but we need to actually look at the allegations first to actually verify that they are true," she said.

Opposition parties want to know when and how the government was first alerted to the allegations.

Government grilled for third day

Today, the Government faced a third day of questioning in Parliament about failings in the child protection system.

Opposition Leader Bryan Green asked how Premier Will Hodgman was unaware of the allegations against Safe Pathways until the Four Corners program aired.

"Premier, why haven't you, after so many failures in the child protection portfolio, stepped in and taken a personal interest in the plight of some of Tasmania's most vulnerable children?," Mr Green asked.

"I have confidence in my ministers and I trust them," Mr Hodgman responded.

The Premier said child protection received more than 13,000 notifications a year.

"That's a disturbing figure," he said.

"I'm not going to be advised each and every time. If there's any former minister sitting over there who was, can they please declare themselves now?"

The review of Safe Pathways will be completed within the next few weeks.