The commonwealth on Sunday announced a $5.7 million community support package for people who have or currently live and work near the Top End's RAAF Base Tindal, where foam leeched into ground and surface water.

Senator McCarthy welcomed the "way overdue" investment for Katherine locals, who may become the fourth class action group to sue the Defence Department after lobbying for free voluntary testing for more than 12 months.

"That's placed extra pressure, and it's the people of Katherine themselves who have pushed the hardest," she said.

From early next year, additional counselling services and an epidemiological study into potential contamination causes and health effects will also be funded.

Ms McCarthy said Katherine residents had deserved the same treatment as interstate communities affected by pollutants from military bases Williamtown in NSW and Oakey in Queensland.

"Listening to the families who've had water trucked in each week by the defence force for them to drink on the rural properties around Katherine, we're talking about a first world country that should not have to be doing that," she said.

On Wednesday Katherine Mayor Fay Miller will travel to Canberra to meet with Health Minister Greg Hunt, where she'll push for cash for tourism promotion and land buybacks to compensate for the town's reputational damage.

"Some people are sitting on properties that are practically useless to them," she said.

The move has been welcomed by the NT opposition and government, with Katherine MLA Sandra Nelson stressing there was still much work to be done for the town's "long road to recovery".

"After a year of lobbying and advocating ... I am so relieved," she posted on Twitter.

Delivered by the health department, the package was informed by the results of an interim human health risk assessment due to be released on Monday.

The full study as well as an ecological risk assessment is due to be completed early next year.

AAP