SYDNEY (Reuters) -Australia is "urgently seeking more detail" on U.S. President Donald Trump's threat to raise tariffs up to 200% on pharmaceutical imports, Treasurer Jim Chalmers said on Wednesday.

Trump announced plans to impose tariffs on pharmaceuticals, as well as a 50% tariff on copper imports, during a cabinet meeting in Washington hours earlier.

"These are obviously very concerning developments," Chalmers told the Australian Broadcasting Corporation on Wednesday.

Chalmers said while the U.S. accounted for less than 1% of Australia's copper exports, the pharmaceutical industry was "much more exposed" to the impact of tariffs.

"Much more concerning are the developments around pharmaceuticals," he said. "And that's why we're seeking - urgently seeking - some more detail on what's been announced."

Medicines and pharmaceuticals are among Australia's top exports to the U.S, with around A$2.1 billion ($1.37 billion) in shipments last year, according to the Australian Bureau of Statistics.

Chalmers also said the Pharmaceutical Benefits Scheme, a national programme that subsidises a wide range of prescription medicines for Australians, was "not on the table" as a bargaining chip to escape the threatened tariffs.

"We're not willing to compromise the PBS. We're not willing to negotiate or trade away what is a really important feature of the health system," he said.

For months, U.S. lobby groups have been pressuring Trump to retaliate against the PBS through tariffs, claiming the "egregious and discriminatory" pricing regime undermines American exports.

($1 = 1.5347 Australian dollars)