LABOR has pledged support for the Turnbull government if it joins a trade war against United States President Donald Trump.

Opposition treasury spokesman Chris Bowen said about $240 million in steel exports and $70 million in aluminium sales to America were at stake.

And other countries could attempt to dump cheap product on the Australian market if denied access to American buyers.

Mr Trump announced he will impose a 25 per cent tariff on steel imports and 10 per cent on aluminium, with no countries to be exempted.

“Well I think that we should look at all options in the national interest,” Mr Bowen told ABC radio. “And as I said, the Government would have the full support of the Labor Party for anything it does to convince the United States, and if that’s not successful then obviously the Government would be within its right to consider what comes next.”

Prime Minister Malcolm Turnbull discussed trade with Mr Trump in Washington last week but was given no assurances Australia would be affected badly by his trade policy.

In fact, the ABC reports Donald Trump “emphatically” promised to exempt Australian steel and aluminium from US tariffs during a meeting last year.

Australian Trade Minister Steve Ciobo at the weekend telephoned US Commerce Secretary Wilbur Ross but was unable to get any clarification. That was because at that stage even senior members of the Trump administration hadn’t been given the details of the President’s plans.

Mr Trump is being told by many sources, including British Prime Minister Theresa May, who telephoned him at the weekend, that the tariffs would hurt America’s allies such as the United Kingdom, South Korea and Canada.

But in a tweet today Mr Trump made clear no allies would be safe from his clampdown on imports. The warning came with a “sorry”, clearly a fake apology.

“We are on the losing side of almost all trade deals. Our friends and enemies have taken advantage of the US for many years,” he tweeted.

“Our Steel and Aluminium industries are dead.

“Sorry, it’s time for change! MAKE AMERICA GREAT AGAIN!”

We are on the losing side of almost all trade deals. Our friends and enemies have taken advantage of the U.S. for many years. Our Steel and Aluminum industries are dead. Sorry, it’s time for a change! MAKE AMERICA GREAT AGAIN! — Donald J. Trump (@realDonaldTrump) March 5, 2018

Mr Trump’s move move could ignight a trade war, with Europe already threatening to put levies on American goods. This could push up interest rates, rock the stock market, and add to global economic uncertainty.

“So clearly this is the number one priority at the moment in the bilateral relationship that Australia should be pressing to the United States,” Mr Bowen said.

“One, an exemption for Australia, and two, more broadly, to step back a trade war here would be very damaging to everybody involved including the United States.

“This is a matter where all Governments in the world are fully entitled to press the incumbent administration on what should happen, and most particularly nations like ours who, we are told, are key strategic allies in the United States.

“We would need to see that reflected in a detailed policy response, not just in words and sentiment.”