Lands Minister Brendon Grylls is facing a Supreme Court battle over the terms of pastoral leases covering about 90 million hectares of WA.
Leading cattleman Don Hoar warned he would take legal action against Mr Grylls if any attempt was made to vary the terms of his lease over 640,000ha in the Pilbara.
Mr Hoar, a veteran of 61 years in the industry, hit out as legal opinion continued to build against a move by the Department of Lands to introduce changes to existing leases when they expire on June 30, 2015.
The real estate industry, banks and investors have warned changes to the lease could create a legal minefield, with the uncertainty causing jitters in the market.
The State Government has already flagged a major backdown over the terms of a draft lease which gave it unprecedented powers of termination and introduced references to a raft of new legislation.
Mr Grylls has asked Nationals WA colleagues Vince Catania and Wendy Duncan to work with the Pastoralists and Graziers Association on a compromise, but Mr Hoar said the Government was legally bound to renew the lease on existing terms.
"We already have a deal in place and I wouldn't have developed and put money into this property without that agreement on the existing lease," he said.
"After 61 years in the industry I don't need a bunch of galahs telling me how to do things."
Mr Hoar invested heavily in Balfour Downs station north-east of Newman and its cattle operations over 14 years before listing it for sale with Elders last year.
He has widespread support in the industry and his lawyer Ross Williamson has asked others to join in the legal challenge, which is based on undertakings the Government gave to extend the leases on existing terms.
"The Minister is now under a very clear legal obligation to give to pastoral leasees a new lease on exactly the same terms as the old lease," Mr Williamson said.
"The department's talk about how they want to have a modern lease and want to introduce new terms and want to do this and that is completely irrelevant and complete nonsense.
"The offer (to extend leases) was made and accepted and it is legally binding under the Land Administration Act."
Primaries real estate consultant Bob Hart said the issue was creating doubt among prospective buyers at a time of renewed interest in investment because of positive signs in the live cattle export industry.
Mr Hart said all parties to a sale were worried about the prospect of litigation if the terms of leases changed in a little over 18 months' time.A spokesman for Mr Grylls said a meeting next week between Government representatives and the PGA would help to resolve the issue.