THE Greens have hit out at Agriculture Minister Barnaby Joyce's apparent backflip on foreign investment, after he welcomed the purchase of a northern cattle station by an Indonesian firm.

Mr Joyce made the comment after the long-standing Northern Territory cattle family, the Underwoods, sold two of their properties to Indonesian cattle importer Santori.

The Deputy leader of The Nationals said he made the decision to support the investment after speaking to NT cattle producers.

It is understood the properties had been on the market for a number of years, but had previously failed to attract a buyer.

Mr Joyce's comments brought criticism from Greens Leader Senator Christine Milne, who labelled it "hypocrisy" after years of his opposition to foreign investment in agricultural land.

She said the minister talked tough on the issue, but was willing to sell the farm, in line with his Liberal Party colleagues.

But Mr Joyce hit back, saying The Greens wanted to shut down the live cattle trade.

It comes as some of Mr Joyce's party colleagues have outlined they will fight a United States proposal to buy the nation's largest grain handler, Graincorp.