One Nation Senator Pauline Hanson says a Turnbull government plan to forcibly acquire farm land in Queensland so Singaporean troops can use it for defence training may be unconstitutional.
Senator Hanson believes the plan fails the public interest test, and claims it may breach the constitution and the Commonwealth Land Acquisition Act.
The One Nation leader has encouraged farmers to take their fight to the High Court, saying they were not properly consulted and the plan will destroy prime agricultural land held by farming families for generations.
"This is about buying up public land for a foreign power, there's no public purpose there," Ms Hanson told reporters in Brisbane on Tuesday.
"This could be challenged by the farmers in the High Court, and if they do so, I believe they have a good case."
The federal government has agreed to let up to 14,000 Singaporean soldiers train each year at the Townsville Field Training Area and the Shoalwater Bay training base, near Rockhampton, by 2021.
Both bases will be expanded to cope with the number of soldiers, with Singapore to spend about $2 billion upgrading infrastructure.
But Senator Hanson says the local benefits being spruiked by the government - including providing troops with food, transport and other services - won't eventuate.
"I have been informed that Singapore is intending to ship out their own food, their own supplies, their own ordinance, and also they own their own food company here."
"So they've tied it all up, and I've also been told they own some of the hotels in Townsville."
Senator Hanson said she wasn't opposed to the Singaporean army coming to Australia to train, and gave several alternate sites where they could set up, including RAAF Base Pearce in Western Australia and a block in Queensland's gulf country.
"There is other land that they can secure, not to take the land from these people who do not want to give it up."
One Nation's stance comes as the National Farmers Federation lobbies the government to rule out the compulsory acquisition of land.
Deputy Prime Minister Barnaby Joyce plans to travel to the town of Marlborough on Friday, however will only meet about half of those affected.
NFF chief executive Tony Mahar said they're worried the government was rushing the process.
"Whether the acquisitions are compulsory or not - taking any farm business out of these local economies will have flow-on affects for small businesses and the employment opportunities for the residential farming community," Mr Mahar said.
"We want advice from the deputy prime minster as to how the government will address this impact."
