A massive trip through the Murray Darling has uncovered water savings which would run to hundreds of billions of litres of water, says the Opposition's Greg Hunt, but only if the Government would start investing in new irrigation technology and infrastructure with farmers.

The Coalition's spokesman for the environment has just completed an epic 3000 kilometre trip, driving from the top of the basin to the bottom and visiting most irrigation valleys on the way, to learn just what can be done to save water ahead of buying up licences from irrigators.

Mr Hunt said he'd push for the infrastructure funding to flow to irrigation communities "as a matter of urgency" when he returns to Canberra next week.

"We found 600 billion litres of water which could have been shared between farmers and the environment in potential water savings if the infrastructure funding was approved and allocated," Mr Hunt said.

"In the Murray-Darling area of Queensland, 120 gigalitres, or 120 billion litres, could be saved.

"In the Bourke area, we found eight billion litres.

"In the Trangie area, 30 billion...and it goes on and on as you go through the system.

"It got to as high as 300 billion litres when we got to the Murray Irrigation corporation region in southern NSW, on the northern border of the Murray.

"It's time the Government let these irrigation funds flow – there's 600 billion litres of water savings which are being wasted by not beginning the investment process.

"The Government must unfreeze the funds and begin the process of re-plumbing rural Australia."

He said the Government was sitting on the money which was budgeted for infrastructure improvements, arguing it was "racking up interest in the bank rather than savings in the field.

"Farmers are ready to make the savings and share the water with the environment but they're not getting the support."

He said in the Murray Valley area the chairman and CEO of Murray Irrigation told him they'd offered 300 billion litres of savings which could all be shared with the environment if they got about $1 billion.

"Now that's 50pc of the savings that we were originally aiming for from one sixth of the funding but it's been thrown in their faces by (Minister for Water) Senator Wong."

Senator Wong has refused to commit to a timeframe for the rollout of the infrastructure investment funds, which is close to $6 billion.

Last month a spokeswoman from her office said the Government has been actively discussing irrigation infrastructure improvements with key irrigation industry stakeholders and relevant state governments.