Mr Carter was one of the speakers at the Otago Regional Council's Water Quality Forum.
More than 100 people attended with farmers, orchardists and grape growers making up the bulk of the crowd.
Mr Carter said Prime Minister John Key and Minister of Finance Bill English had already said they were "open to" the idea of direct Government funding for regional irrigation schemes.
"But in saying that, any proposition for Government funding would have to demonstrate that all other commercial solutions had been exhausted.
It would also have to demonstrate that the wider community stands behind the proposal."
Mr Carter said any proposal would also have to demonstrate a commitment to good management of water and nutrients.
"If all these boxes are ticked, I can assure you we will consider the role of central Government funding to get the progress this country needs on water storage and management."
Accelerating reliable irrigation was one way to promote growth in the rural sector.
However, any increase in irrigation would mean more intensive farming, so there would be an environmental impact.
"This is why, whenever I talk about removing regulatory roadblocks to water storage and irrigation, I stress we must also maintain high environmental standards."
The Government already provided substantial funding opportunities for irrigation schemes to be developed, he said.
The scope for applicants for the Community Irrigation Fund had been widened to include local government agencies developing water strategies and there was also opportunity for grants via the Sustainable Farming Fund.
Four Otago schemes - Dairy Creek, Tarras, Taieri and Mt Ida - had so far received a total of more than $900,000 in Government funding.
All the questions from the floor for Mr Carter revolved around irrigation.
Speaking outside the forum, he said it was ironic to be discussing irrigation on an unusually wet day in Central Otago.
"If I'd been here a week ago, we'd have been talking about the drought.
"That's what I was talking about in Oamaru at the weekend, and now it's flooding.
"That's how rapidly things can change.
"I think there's more of this sort of weather to come, with climate change."
The Government wanted to ensure that the region developed an "optimal plumbing solution" for Otago.
If communities were behind irrigation schemes, and all the boxes were ticked, Government would do its best to help, he said.
