The National Party has dismissed ongoing concerns about funding for the Parkes telescope as "mischievous", saying Labor's $250 million plan to increase CSIRO funding is unsustainable.

The Federal Opposition is promising "one of the largest investments in science" in Australian history and said it would shore up the long-term future of the CSIRO-operated Parkes dish.

Concerns were raised earlier this month after leaked documents obtained by Fairfax showed the facility could be closed because of a looming funding shortfall, with extra money being allocated to the Australia Square Kilometre Array Pathfinder in Western Australia.

Unions have welcomed Labor's CSIRO funding announcement after earlier demanding clarification about the future of the Parkes facility.

Nationals member for Riverina, Michael McCormack, said he had repeatedly received assurances from the Science Minister Christopher Pyne that the future of the dish was secure.

"CSIRO has said that it hasn't got any intentions to scale back what we're doing there," Mr McCormack said.

"I think those reports were mischievous, and that's what [Labor] is good at during the election campaign.

"But we understand that science is a huge part of everything that we do and certainly, that's why Christopher Pyne has that dedicated portfolio, to make sure that not only is the funding secure, but to make sure the work is getting done."

Opposition says funding certainty needed

The dish was involved in a major scientific breakthrough announced this week, with the detection of a first-of-its-kind molecule in space.

Labor's candidate for Riverina, Tim Kurylowicz, said the aim of the $250 million commitment was to "undo the damage" caused by funding cuts in the 2014 budget.

He said while it was up to the CSIRO how much of that funding would go towards the Parkes dish, it would help secure its future and continue making internationally-significant discoveries.

"Unless the funding is put back into the CSIRO, that facility's going to fall further and further behind," Mr Kurylowicz said.

"If it can't keep up with the latest science research then what's the point of having it there? It's not going to continue to win grants and do cutting-edge research."

But Mr McCormack expressed scepticism at Labor's funding commitment.

"Labor's pledging to spend a lot of money on a lot of things; I'm not quite sure how they're going to pay for all these things," he said.

"At least our policies are fully-costed, and we're working towards certainly providing all the sorts of things that a federal government should provide."

Potential for 'innovative' ways of funding Parkes dish

Mr McCormack said government funding for the CSIRO was, in fact, growing with indexation.

But he suggested there was also scope for looking at innovative ways of funding science infrastructure, including sourcing more funding from the private sector.

"I spoke to the Parkes mayor Ken Keith about this very thing this morning," he said.

"In July they've got an astrophysics forum happening in Parkes, to hear about those sorts of funding options because there are innovative ways that we can fund this.

"Private people do want to get onboard for all the great work that's been done here in the past but indeed, what we'll be doing in the future."