Representatives from the Federal Environment Department have told Senate estimates they won't rule out calling for a fresh scientific investigation into the impact on water resources from the Shenhua Watermark coal mine.

It was in response to questioning from Queensland Greens Senator Larissa Waters.

She asked the Department if it would seek updated water advice from the Independent Expert Scientific Committee, given the last advice was prepared in May 2013.

Senator Waters said it's imperative the government seek updated advice before it makes the final decision.

"Given the change to the mine plan and the fact that the advice was commissioned before the water trigger actually took effect, I think it's a really strong case to update that advice," she said.

"The IESC should have another look at this project and give the Minister the full information on just how dangerous the Shenhua mine is going to be to our groundwater and our surface water."

The current assessment timeline would see a decision by March 13, but if the Department decides it needs updated advice from the committee or the proponent, the timeline would be paused.

"The department has confirmed they can press pause on that timeframe and seek further information, either from this expert water committee or from the proponent," Senator Water said.

"So that's positive news in that it's a possibility, and hopefully the pressure that those questions have placed on the Department and the Minister may well lead to the water committee having another look at this project."

Senator Waters said the Government needs to be sure of it's decision.

"A decent Environment Minister would say 'Yes we're going to have another look to make sure that we've got the full information,' so let's see if the Abbott government does actually want to look at current science or whether it just wants to waive through this massive coal mine on our best food producing land."