Trade Minister Craig Emerson has rejected claims his support for Chinese investment in northern Australia has been influenced by the reported business interests of former Labor prime minister Bob Hawke.

The Government wants China to invest in land in northern Australia, as part of a deal to increase food exports.

There are unconfirmed reports Mr Hawke is representing a Shanghai-based company wanting to farm all 15,000 hectares of the land being developed as part of the second stage of the Ord irrigation project in Western Australia.

The Ord River area is home to some of Australia's most prized agricultural land and is one of the sites up for consideration, as is the Atherton Tableland in Queensland.

Nationals Senator Barnaby Joyce used an estimates hearing on Thursday night to claim that Mr Hawke's interests have influenced Dr Emerson.

But the Trade Minister rejected the claims, labelling them "typical gutter politics".

Dr Emerson has previously stated the proposal was designed to lift food production for world markets.

A joint study with the Chinese government into the proposal is expected to be released within months.

Senator Joyce says he has no problems with boosting Australia's foreign food exports but he says greater efforts should be made to ensure Australians own as much farming land as possible.

He says policies are needed to ensure farming land is purchased by Australians before foreigners.

"In our national interest, we should be getting the biggest footprint on our own country developing our own food for sale to the world," he said.

"What we're seeing with this is basically mechanisms for another nation to get their footprint on our land.

"Good luck to them. It's a very smart thing to do and it secures their food future and they're saying exactly that."