Barnaby Joyce has flagged possible changes to a landmark Pacific-wide trade deal agreed to last week if needed to bring the United States on board.

Australia, New Zealand, Canada and Japan are among the 11 nations that agreed on Tuesday to the Trans-Pacific Partnership, which was thrown into disarray last year when US President Donald Trump pulled his country out.

Prime Minister Malcolm Turnbull was lauding the deal for much of last week, saying it would be signed in Chile in March.

But the deputy prime minister says the agreement reached isn't yet final.