The Katherine Times was alerted this morning to the success of mediation talks between Department and Defence lawyers and the legal teams representing Katherine, Williamtown and Oakey.

We have been informed by the office of Senator Malarndirri McCarthy that in-principle agreement has reached to settle the claims.

Katherine's class action was taken up by Shine Lawyers.

The basis of the legal action is that "contamination by PFAS has negatively impacted business and land values in Katherine".

The chemicals were contained in fire foaming foams used mainly in training at the base from 1988 to 2004.

Most Katherine property owners, and at the last minute the Katherine Town Council, have sought compensation from Defence for the falls in property values across the town which has come from the PFAS contamination.

PFAS was used in firefighting foams once used at the base in training and continues to leak off the base into the groundwater and directly under Katherine.

Some properties neighbouring the base are thought to be unsaleable.

The mediation talks have been held over the past two days.

The class action taken by residents living on PFAS affected properties near Williamtown, Katherine and Oakey military bases against the government had been set down to be heard in the Federal Court of Australia from April 1.

While repeatedly admitting fault in allowing dangerous chemicals to leak from the Tindal RAAF Base, the Defence Department is contesting the claim that PFAS contamination caused property values in each area to drop.

The parties are in the process of finalising the terms of the settlement.

"These terms are confidential and are subject to formal consideration and approval by the Federal Court of Australia," a joint-statement issued by Defence Minister Linda Reynolds and Veterans Affairs Minister Darren Chester said.

"The parties will inform the Federal Court of Australia that an in-principle agreement has been reached at the first available opportunity."

A spokesman for Williamtown's residents' legal team said: "We note the government's statement as an important first step to clean up this mess in communities," he said.

"We will release a statement on Thursday morning after which our legal team will begin the process of updating class action members."

The ministers' statement said the government remained committed to engaging with those impacted by PFAS contamination.

"Reaching a settlement is not the end of defence's engagement in these communities, however, it does represent an important milestone on what has been a difficult journey for many people over the past few years," it said.

"The government remains committed to concluding the environmental investigations into PFAS contamination on and near defence facilities across Australia, and to the ongoing monitoring and engagement with communities once investigations are complete."

Prime Minister Scott Morrison said in Katherine last week that the government would approach the mediation process in good faith.

"...previous governments have just kicked that can down the road," he said.

"Our government hasn't, we've stepped up and we're engaged in mediation with those communities now."

Senator Malarndirri McCarthy said: "Whilst we're yet to see the final details of the Federal Government's offer, it's positive news that the Federal Government is finally stepping up and doing the job it was meant to do for the families suffering.

"I am pleased for the people of the Northern Territory, particularly Katherine, who gave evidence to our inquiry in 2018.

"I have pursued this continually on behalf of the residents of the NT and will continue to do so until there is a satisfactory outcome.

"I call on the Federal Government to now respond formally in the Senate to our report that was tabled in November 2018."

More reading: Katherine's grim PFAS timeline.