Nationals leader Barnaby Joyce says a re-elected Coalition would create a new national body to administer the Commonwealth's concessional loans programs, but he's avoided questions about the constitutionality of that arrangement.

Previously, when asked whether the Coalition would consider establishing a single national body to administer, assess and allocate concessional loans for drought-hit farmers, Mr Joyce has said constitutional issues would prevent that.

The programs are currently administered by the states, in an arrangement which has been blamed for slow and inconsistent delivery of loans.

At the National Press Club, Mr Joyce said the need for a national body is clear.

He cited a delay in extending concessional loans to struggling dairy farmers, which he blamed on a Victorian Government demand for more administrative funding from the Commonwealth to deliver the scheme.

"The Commonwealth should not have to offer drought or other support through the states after the establishment of this Regional Investment Corporation," Mr Joyce said.

"We will have a vastly more streamlined way to act."

The new body would also administer the Water Infrastructure Loans Facility, and any future Commonwealth concessional loans program.

Labor offers 'in principle' support

Labor's agriculture spokesman Joel Fitzgibbon said he had no problem with the principle of Commonwealth administration of the concessional loans.

"But who administers the program is not the question," he said.

"The real question is, have concessional loans proven to be an effective tool in responding to drought. As each day goes on we come to the conclusion that they're not."

Mr Fitzgibbon has supported drought loans and the extension of loans to dairy farmers in crisis, but said they should be treated as "one tool, that will help some people, not a panacea",

Constitutional questions unanswered

The Commonwealth has offered concessional loans to drought hit farmers since 2013, under both Labor and Coalition governments.

They've been heavily criticised by the National Audit Office, and by farmers who cited inconsistent application of eligibility and other loans criteria between states.

Outside the Press Club on Wednesday, Mr Joyce would not directly answer questions about how the proposed Regional Investment Corporation would overcome his previously stated constitutional concerns.

Instead, Mr Joyce noted the previous existence of similar organisations in the past.

"We've had in the past development-type banks, the Commonwealth Development Bank being a classic one, in fact my family got a start with the Commonwealth Development Bank," he said.

"We've done it in the past, so I don't think there's going to a big issue with constitutionality."

That's in sharp contrast to Mr Joyce's comments last year, when the Coalition extended its drought loans programs for another 10 years as part of the Agricultural Competitiveness White Paper.

At the time he said "God gave us Adam and Eve and the constitution gave us the states" and said the Commonwealth didn't "have authority" to administer loans itself.

He also warned that the administrative costs of establishing a national body and "duplicating" existing state organisations.

"Therefore the money wouldn't be going to the farmers, it would be going to setting up buildings and computers and wages and salaries, and why would you do that?" he said at the time.