Lawyers have met with residents in Katherine to talk about a potential class action.

The Northern Territory town could become the third place to sue the Defence Department over contamination linked to PFAS firefighting foams once used on Air Force bases.

Hundreds of people turned up to hear from Shine Lawyers, the same firm behind a PFAS class action in Oakey, Queensland.

Per-and poly-fluoroalkyl substances, also known as PFAS chemicals, were in the foam used at RAAF bases - including at Tindal near Katherine, until 2004.

At several sites they have been found to have seeped into bores and infiltrated drinking supplies.

“They've got to pay for what they've done to the Katherine water table and the people,” Katherine resident Lillian Smith told reporters.

“I've got health problems and I think it is caused by that [PFAS] because I lived on Uralla Road for 10 years and I was drinking that water, the bore water, and showering in it. Doing everything with bore water.”

Special counsel at Shine Lawyers Joshua Aylward said the class action could seek compensation for several issues.

“The claim for the people of Katherine will be for property values, it'll be for business losses, it'll be for stress and for vexation and it'll be for breaches of statutory duties as well as nuisance and negligence,” Mr Aylward said.

“Ballpark figure ... hundreds of millions [of dollars] would be what is entitled to the people of Katherine for the loss that they've suffered here.”

Dozens of residents rely on bottled water provided by Defence, while water restrictions have been imposed to keep the town's drinking supply within accepted limits.

If the class action goes ahead in Katherine, residents will join two other similar cases involving almost 1,000 people in PFAS-affected areas in Queensland and New South Wales.

“They're concerned about their town water, they're concerned that there are many ways in which these chemicals are entering their body and the environment around them and they're concerned that their properties are not worth anything like they used to be,” Mr Aylward said.

“And they're concerned also that the Department of Defence is being extremely slack and has not been investigating this soon enough.

“I absolutely think it [a class action] will go ahead and what we've seen in the other towns is that momentum builds and people sign up pretty quick,” he said.