As at this week, there are 46 "non-litigated" claims on Defence.

These are outside the class actions made by Katherine, Williamtown and Oakey residents.

Only three of them have been resolved despite Defence urging people to consider the "non-litigated" path rather than joining the looming Federal Court action.

There were 41 individual claims against Defence outstanding a year ago, made over the preceding four years.

This week Defence's lead PFAS spokesman Steve Grzeskowiak told a parliamentary inquiry the number was now 46.

One of them had been resolved with an Oakey resident and another two were satisfied with Defence help, which the Katherine Times understands was the supply of rainwater tanks in one case.

Some of those "non-litigated cases" are known to be from the Katherine area.

But Members of Parliament wanted to know why other claims are not being resolved.

Mr Grzeskowiak was speaking at the second hearing of a PFAS inquiry conducted by the Joint Standing Committee on Foreign Affairs, Defence and Trade in Canberra on Monday.

He was pressed by Labor's Meryl Swanson whose electorate of Paterson includes Williamtown.

"What's the hold-up? Why are there still 46?" she asked.

Mr Grzeskowiak said the "process" was run through the legal side of Defence.

He said the Attorney-General was "following the Commonwealth's Legal Services Directions".

"I'm certainly aware that on a number of those claims there are ongoing conversations. I don't have any more details," he said.

More reading:

PFAS in Katherine - timeline.

Earlier in the hearing, Mr Grzeskowiak said Defence was continuing its efforts to fix those areas where PFAS contamination was now known to have happened, like Katherine.

"But I've been saying for a little while we'll never remove all of the PFAS from the environment, because it's just out and about and spread out.

"But what we're seeking to do is reduce as much as we can and to continually refine our efforts to target hot spots, if you like, so that we get the best value in terms of the amount of product that we can remove from the ground, all the time with a focus on, if we discover exposure pathways for people, how do you remove that exposure pathway?"

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