A spokesperson for the Department of Agriculture, Water and the Environment (AWE) said the Commonwealth supported the just resolution of legal claims by agreement, not litigation, where appropriate.

"All legal claims are handled in accordance with the Attorney-General's Legal Services Directions 2017," the department spokesperson said.

"If these claims are unable to be resolved at mediation, they will proceed to a hearing in the federal court. As the matters are currently before the court, it would not be appropriate to comment further."

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

Ben Allen from Dentons, the global law firm leading the Williamtown class action, confirmed that the parties would enter court ordered and confidential mediation.

"While this has been one of the faster class action proceedings it has taken time to get to this point and the community remains resolute about getting a just outcome to this contamination travesty," he said.

Earlier, Coalition Against PFAS (CAP) president and Fullerton Cove resident Lindsay Clout said that new information - the release of a US movie and a crucial stop work decision made in Victoria - had hardened the resolve of group members in their quest for justice.

"We feel we have no option but to go ahead with legal action after having been let down by government and regulators," Mr Clout said.

Mr Clout said that a critically acclaimed Hollywood movie about a US PFAS case called Dark Waters tells the 2017 story of a US$671 million settlement on behalf of more than 3500 plaintiffs whose water and land had been contaminated by the chemical PFAS.

"One of the things that was highlighted [in the movie] was how both government and regulators in the US totally failed to protect communities against PFAS contamination," he said.

"More recently we saw the shutting down of a $6.7 billion road tunnelling project in Melbourne because workers came across PFAS-contaminated soil.

"This project wasn't halted simply because a regulator said it couldn't go ahead. It wasn't halted because of legislation. It was instead two of Australia's biggest construction companies who said they were not prepared to put their workers at risk.

"That decision only highlights the contempt both state and federal governments have treated families in Williamtown, whose homes and properties are also contaminated. For more than five years the federal government has said there's not an issue with PFAS contamination still leaking off the Williamtown airbase.

"Well when big business on a multi-billion project says PFAS exposure is too dangerous for their employees it highlights the lack of policy, clarity and decency government has towards thousands of ordinary Australians.

"Our political leaders and health and environmental regulators have utterly failed PFAS-contaminated communities like Williamtown.

"Rather than running their third PFAS inquiry in four years the government needs to actually take action, just like business and unions have made it clear they won't do the same with their workers."

The AWE spokesperson said that the Australian government was aware of media reporting of the legal proceedings in the United States against the chemical manufacturer DuPont [portrayed in the movie].

As for reports of government funding being put aside to fight the class action, the spokesperson said "there is no funding provision put aside within in the Commonwealth or Defence budget for PFAS related class actions or compensation. Potential PFAS liabilities are identified as an unquantifiable contingent liability in Defence's financial statements".

"Questions about delays to the West Gate tunnelling project are a matter for the Victorian state government," the spokesperson added.

"However, we can advise that the project has not been shut down and work is still underway with all appropriate safety measures in place. Low levels of PFAS have been identified on some West Gate tunnel project sites.

"The project is working with the Victorian EPA and Worksafe to ensure contaminated soil is managed and removed safely.

"Victoria's approach is in-line with nationally consistent practices outlined in the PFAS National Environment Management Plan, which is developed, agreed and implemented by all jurisdictions."

The spokesperson said that the government had taken a precautionary approach to managing existing PFAS contamination and was working to prevent or reduce environmental and human PFAS exposure wherever possible.

"For most people living in PFAS affected areas, the highest risk of exposure is likely to be through the direct consumption of contaminated groundwater (i.e. bore water) and food grown using contaminated groundwater. Dermal (skin) contact with PFAS is not considered a significant exposure pathway."

Williamtown resident Linden Drysdale said that she wished the politicians and government members could live for one week the lives PFAS-impacted residents have lived for five years now.

"While the governments and lawyers attend mediation the residents continue to live in fear. I am not sure how or what to feel about the upcoming mediation and court action, I just want this whole episode to be over. It would be fitting if we could finally get an outcome that is favourable to the residents," she said.

Meanwhile, Paterson Labor MP Meryl Swanson said that she had pleaded with the Attorney-General to settle the matter outside of court, "and I understand that this battle is ongoing. Regardless, it is a disgrace that it has come to this".

Ms Swanson added that the Labor Party's policy platform [on PFAS] was under review following last year's election result.

"It is up to the Coalition government, who have been in office since 2013, to use all the resources at their disposal to investigate issues of concern to the community and put forward solutions.

"Labor will look at every opportunity to form a bipartisan approach to this matter, but the Government is ultimately responsible for addressing issues associated with PFAS contamination," she said.

"The Morrison government could start by finally releasing its response to the recommendations of the inquiry into the management of PFAS contamination by the Joint Standing Committee on Foreign Affairs, Defence and Trade."