The Federal Government is being "complacent" as researchers behind a study of the effects of PFAS contaminants still lack permission to use blood test samples and results from residents in Katherine, a doctor says.

In December, the Federal Government announced a $5.7 million support package for the Northern Territory town of Katherine, about 350km south-east of Darwin, to fund voluntary blood testing, counselling and an epidemiological study, after considering an interim human health risk assessment conducted by the Defence Department.

The epidemiological study will look at the incidence, distribution, and control of diseases stemming from PFAS exposure, and blood tests have also been carried out in the PFAS-affected towns of Williamtown in NSW and Oakey in Queensland.

The free blood testing became available for Katherine residents in March, with hundreds of people taking up the service after giving written consent for their results to be used as part of the study.

However, almost two months later, the Australia National University's study team is yet to gain approval from an NT ethics body to use the data — and it only applied to obtain permission this month.

Katherine doctor Peter Spafford questioned why it was taking so long, considering permission had been granted for Williamtown and Oakey.

He also said that as of last week, the study team had also not begun analysing the results from Williamtown and Oakey, and the uncertainty was affecting residents, he said.

"This does concern me that no-one appears to even have looked at the results from Williamtown and Oakey … combined with the fact that ANU still doesn't have ethical approval to undertake any study here yet," Dr Spafford said.

"I'm sure there are good reasons for all this delay, but it underlines the fact that the Government has been very complacent about all this.

"The people of Katherine are concerned about the levels of PFAS here, and I'm sure people living in other areas of contamination are, too."

Dr Spafford said the delay in collating the results was "a disaster".

"What I want to know is, is this a national problem? Are we alone in this, or do we share our concerns with others? We have no information on this apart from concerning figures," he said.

Legacy issues with toxic chemicals from firefighting foam in waterways remains a national issue. ( Supplied: CRC CARE )

50 times US chemical levels recorded in Katherine residents

Dr Spafford said his clinic had taken blood samples from almost 200 people so far, and said the rates of the chemical PFHxS were alarmingly high.

"The Australian levels are much higher than those considered acceptable in Europe, for example," he said.

"Our average is five times the upper limit of the population figures of the United States, we're seeing up to 50 times the upper level of normal in the United States."

He said there continued to be a lack of information and clarity around what the numbers meant.

"I don't know how to reassure my people," Dr Spafford said.

"People are confused, and as soon as you get confusion, you get concern."

Map Defence Force toxic chemical contamination sites

No blood tests given to ANU before approval: Govt

A spokeswoman from the Federal Health Department said the ANU study team submitted an application to the Human Research Ethics Committee (HREC) of the NT Department of Health and Menzies School of Health Research on May 4.

"The HREC is currently conducting an expedited assessment of the application," the spokeswoman said.

"Once HREC approval has been provided, and where individual consent is given, this will allow ANU to receive blood-testing results and samples that have been collected through the Voluntary Blood Testing Program for the RAAF Base Tindal investigation area."

The spokeswoman said no blood tests or samples would be provided to ANU before approval.

She said people who have already been tested would be contacted by ANU to give their consent to provide the results to the study, and to take part in future components of the research.

This month, an expert health panel formed by the Australian Government found there was no evidence PFAS chemicals are linked to human disease; however, Dr Spafford said the panel's findings had not addressed residents' concerns.

NT Health Minister Natasha Fyles has said the Federal Government needed to prioritise long-term studies into PFAS.

The NT Department of Health has been contacted for comment.