Opposition Leader Tony Abbott has promised to tighten rules for foreign investment in Australian farms, attracting claims he is pandering to populism and putting the economy at risk.
Mr Abbott has proposed setting up a national register for foreign-owned property and forcing overseas buyers to seek Foreign Investment Review Board approval for agricultural land purchases of $15 million or more - down from the current $244 million threshold.
The FIRB also would consider the foreign purchase of agribusinesses exceeding $53 million, or a stake of 15 per cent or more in an agribusiness, the new discussion paper says.
Membership of the board would be expanded from five to seven members, including at least one person with agricultural sector expertise.
Mr Abbott said the public needed to have confidence that any foreign investment was in the national interest.
While foreign investment was vital to economic growth, the thresholds and guidelines for the general business sector were "not necessarily the right settings for agriculture", he said.
"We believe proper oversight can provide greater certainty to investors and ensure there is greater confidence in the Australian community that the investment taking place in agriculture and agribusiness is in our national interest," Mr Abbott told reporters in Sydney.
Nationals leader Warren Truss said Australians needed to appreciate the importance of food security.
However, former Howard government minister and farmer Peter Reith said the proposals were short-sighted.
"Pandering to populism is contrary to public interest," he said on Twitter.
Treasurer Wayne Swan said the discussion paper was "all over the shop".
"It's a dog's breakfast," he told reporters in Adelaide.
"We've got a range of possibilities canvassed in this paper that just send very confusing messages about what the Liberal Party stands for."
Trade Minister Craig Emerson said the coalition was manufacturing a problem where one didn't exist, pointing to a "negligible" 0.1 per cent rise in the level of foreign ownership of Australian agricultural land between 1984 and 2010.
National Farmers Federation president Jock Laurie backed a register for foreign-owned land, something Labor also is examining.
But Mr Laurie said the register must be established first before a decision was made on investment thresholds.
"Having a full understanding of foreign investment is crucial to getting the policy decision right," he said.
The Australian Greens say a register is important to build political consensus on the importance of keeping local agricultural land and water in Australian hands.
A register and transparency provisions were vital first steps for the community to make informed decisions, Greens leader Christine Milne said.
Independent MP Bob Katter said Australian farmers would continue to sell to the highest bidders, who at the moment were foreigners.
Australian governments had no concept of building for the future of the country, he said.
"They've already sold our mineral wealth. Now they want to sell our land and pastoral wealth."