The two superpowers are raising tariffs on each other, but Trade Minister Steve Ciobo is buoyed by the way other countries have re-committed to free trade.

"There's been a reaction to that in other quarters, that says 'we're going to double down in terms of liberalising market access'," he told ABC radio on Wednesday.

"That's presenting a rich vein for Australia."

Treasurer Scott Morrison says he will take up the push for more free trade at the G20 finance ministers meeting in Argentina this weekend.

"We have been fighting to keep the doors open to trade. That's good for Australia," he told reporters in Tasmania.

"No-one wins from a trade war. And we need to ensure that we continue to provide the leadership and the advocacy for trade that prevents economic self-harm being done to the global economy."

Mr Ciobo, who is in London, also says Australia has to be "realistic" about the kind of free trade deal it can do with the United Kingdom if it stays in the European Union's customs union.

The UK is negotiating with European leaders about leaving the EU, but the finer details of how it happens have implications for Australia's plans for a deal.

Australia will have to wait to see what gets decided before it can pursue a free trade agreement with the UK, the minister said.

"I think we need to be realistic. It is perfectly understandable that the UK is going to seek to do the best deal that they can with the EU," he said.

"It's a massive market right on their door step, and realistically that is going to preoccupy their focus and attention.

"Once they work out ultimately what that shape will be, that is when Australia can engage in a substantive way."

Australian Associated Press