Residents in Williamtown, near Newcastle, will be connected to town water as part of a New South Wales Government plan to help those affected by contamination from a local RAAF base.

It was announced in September that chemicals once used in firefighting foam at the Williamtown RAAF base had leached into ground and surface water.

A ban was imposed on local fishing and residents have been told not to drink bore or tank water.

NSW Premier Mike Baird said the contamination was deeply concerning.

"We recognise the enormous effect it has had on local residents and businesses," he said.

"We have been in discussion with the Department of Defence to stress we expect it to provide financial assistance to those affected.

"However we believe the Williamtown community should not have to wait any longer for help, which is why the NSW Government is taking decisive action."

The Government will connect affected properties within the investigation area to town water, invest in new contamination testing equipment [and] employ additional community liaison staff to help address concerns of the local community.

A Senate inquiry heard that Hunter Water tested for dangerous chemicals leaching from the Williamtown RAAF base three years before Defence revealed the site's contamination.

The inquiry, being held in Newcastle, was looking into contamination stemming from toxic chemicals once used in firefighting foam at Australia's Defence bases, including Williamtown.

Water Minister Niall Blair said affected properties, which are currently using bore and tank water, will be connected to the Hunter Water network.

"Town water will give locals confidence in the long-term integrity of their water supply," he said.

EPA could have been 'more proactive'

Environment Minister Mark Speakman today confirmed that Professor Mark Taylor has delivered his interim report into historical management of contamination at the base.

He said Professor Taylor found the Environmental Protection Agency (EPA) could have been more proactive in its management of the contamination in the period 2012 to 2015.

But he said the actions of the EPA and other NSW Government agencies since August 2015 have been "responsive, timely and appropriate".

"If there is room for improvement by NSW then it is the role of a responsible government to learn from the past and we intend to do just that," Mr Speakman said.

Mr Speakman said the Government was filling a void that Defence had so far left.

"Defence is the polluter in this case and the polluter must ultimately pay," Mr Speakman said.

"The NSW Government is today repeating its call to the Department of Defence to expedite its efforts to help the community."

He said the NSW Government would also purchase a new liquid chromatography-mass spectrometer, to speed up testing of soil, water, biota and milk.

Port Stephens MP Kate Washington addresses the senate inquiry into contamination stemming from toxic chemicals once used in firefighting foam at Australia's Defence bases. ( ABC News: David Marchese )

"The sooner testing is completed, the sooner we will have the information needed to address both contamination and community concerns."

Parliamentary Secretary for the Hunter Scot MacDonald said the State Government was impressing on the Commonwealth that they had a duty of care to the Williamtown community.

"We can argue the merits and the rights and wrongs of who should pay for it at some stage, but it's more important to do for the community what we can as quickly as we can and argue later on about who pays the bill," Mr McDonald said.

"Hunter Water has now been directed to ensure water connection, I think it's for 190 residents and the connection will include right up to the residence.

"Normal water reticulation just goes up to the house boundary but this will include plumbing right up to the house. So it's a significant investment.

"There's also money for community engagement, drop in centre, there's more assistance for mental health support, there's more assistance for the expert panel."

Mr MacDonald said Hunter Water would commence the planning process, which would take about a month now, and works would begin in February.

He said the project would take about 12 months.