Shine Lawyers has filed an “open” class action against Defence on behalf of everyone, not just those hundreds who have already signed up.

But any others won’t be directly involved.

Defence has already indicated in other cases already presented in Oakey and Williamtown it intends to contest the cases.

But as the case reaches court, it is expected residents who want to “opt out” of the action will be allowed to.

“An open class means that anyone that fits within the ‘class definition’ is part of the class action,” Joshua Aylward from Shine Lawyers said.

“Essentially, this means that everyone who owns a property or business within Defence’s Investigation Area are part of the action,” Mr Aylward said.

The class action has been filed on behalf of members of the Katherine community who own, or either own, residential or commercial property or businesses in the investigation area at November 23, 2016.

It is alleged that the contamination by PFAS has negatively impacted business and land values in Katherine.

The Katherine class action follows the launch of a class action in Oakey by Shine Lawyers against the Department of Defence.

The Katherine class action is not a claim for personal injuries relating to exposure to PFAS contamination.

“The people who have signed up are the core group of claimants,” Mr Aylward said.

“As these people have registered, we are able to keep them updated and more involved in the action going forward.

“Their information and personal circumstances will also assist in guiding the action.

“People who haven’t registered won’t be directly involved in the action.

“Although anyone who fits the ‘class definition’ is automatically included in the action, the court will order that an opt-out process occur at some point during the action.

“This is where anyone who doesn’t want to be part of the class action can opt-out.”

Mayor Fay Miller was reported to have ABC Radio on the weekend she was upset not to be have been informed of the class action.

Ms Miller reportedly said she had been “too busy” to attend several public meetings on the issue in Katherine.

The class action has been widely reported in the Katherine Times over the past year.

There is no indication yet when court action will begin but it could take months and likely years.