Govt offers NT water amid toxic foam scare

Residents of a Northern Territory town who could be impacted by defence base pollutants will be offered alternative drinking water.

Toxic firefighting foams have leeched into ground and surface water near defence sites across the country, and the federal government is investigating whether it extends to the Tindal RAAF base outside Katherine.

The Defence Department has made the offer to Katherine landholders whose properties have been tested along with the RAAF Base and Robertson Barracks in Darwin.

The findings of the preliminary report are expected to be released by early November.

The samples were collected in June and Katherine mayor Fay Miller says people are concerned about a lack of information or consultation from authorities.

"We're very anxious to read the report ourselves ... the sooner it's released the better it will be for all of us," she told ABC local radio.

There are 18 RAAF sites around Australia which have been similarly affected by contaminated groundwater, including bases in Victoria, Queensland and NSW.

More than 400 residents north of Newcastle launched a class action against the Defence Department on Thursday.

Locals there have been cautioned against drinking bore water and eating locally-grown produce while homes have been significantly devalued.

The federal government in June committed $55 million from the current defence budget to cleaning and managing the toxic chemicals.

It will also fund blood tests as well as health and counselling services.