The US Supreme Court on Friday ruled Donald Trump's sweeping global tariffs illegal – a stunning rebuke of the president's signature economic policy that upended international trade.

The conservative-majority high court ruled six-three in the judgment, saying that a 1977 law known as the International Emergency Economic Powers Act (IEEPA) Trump has relied on "does not authorize the President to impose tariffs."

The ruling does not impact sector-specific duties Trump separately imposed on imports of steel, aluminium and various other goods. Several government probes which could lead to more sectoral tariffs remain in the works.

But the justices did not address the degree to which importers can receive refunds.

Top Democrat on the Senate Banking Committee Elizabeth Warren cautioned there remains "no legal mechanism for consumers and many small businesses to recoup the money they have already paid."

US trading partners on Friday cautiously welcomed the ruling, with hard-hit Canada saying the levies were always "unjustified."

A lower trade court ruled in May that Trump overstepped his authority with across-the-board levies and blocked most of them, but that outcome was put on hold as the government appealed. (AFP)



Edited by Robert Kemp