Strong opposition has again been raised against a proposed coal mine expansion in NSW.

The NSW Department of Planning, Industry and Environment (DPIE) has concluded that Whitehaven Coal's Vickery Extension Project can be approved subject to some conditions.

The plan involves during doubling the water extraction rate at Whitehaven’s Vickery mine, between Gunnedah and Boggabri.

The expansion would increase the disturbance area of the mine by 20 per cent, and carry the impacts of building a new rail loader and coal handling facility.

During two days of public hearings into Whitehaven Coal’s plan, several groups told the Independent Planning Commission (IPC) that they do not trust the company’s will comply with some requirements.

The potential impact of the mine on water sources used by farmers was raised as a major concern.

The DPIE claims that even under dry conditions, there would be sufficient licences and water available for the operation of the mine.

Nearby landholder James Barlow told the hearing that the claim has already been disproven during the recent dry period, when Whitehaven reportedly purchased additional land and then piped water to its mines.

“There were issues around water for them without the Vickery mine even up and running,” Mr Barlow said.

Whitehaven Coal was asked whether it would lower the rate of extraction during dry periods.

“To the extent that limitations in procuring licences [occur] … there is always the potential to modify production,” Whitehaven chief executive Paul Flynn said.

“There's also the option of changing the product mix that comes from the site.”

Boggabri farmer Sally Hunter from the group People for the Plains said this is not what Whitehaven did when its Maules Creek mine was running low on water last year.

“Never once did they consider producing less coal and not using so much water,” she said.

“We saw them aggressively buy out water in the market, paying three times the usual prices.”

A final decision expected in August.

Also this week, the Natural Resources Access Regulator announced it is taking the Whitehaven-owned Maules Creek Coal to court, charged with two counts of taking water without an access licence.