California Governor Gavin Newsom has filed a lawsuit challenging President Donald Trump's spate of tariffs that have upended global trade.

The suit, which marks the first time a state has sued over the levies, challenges an emergency power Trump cited, giving him authority to enact them.

California is the world's fifth-largest economy, outpacing every US state and most countries, and is home to the largest shares of manufacturing and agricultural production in the US.

The White House, which has argued the tariffs are tackling imbalances in international trade, dismissed the lawsuit and said it would continue addressing "this national emergency that's decimating America's industries".

"Instead of focusing on California's rampant crime, homelessness, and unaffordability, Gavin Newsom is spending his time trying to block President Trump's historic efforts to finally address the national emergency of our country's persistent goods trade deficits," White House spokesman Kush Desai said.

Newsom and the state's Attorney General, Rob Bonta, announced the lawsuit at a news conference at an almond farm, one of the biggest crops California produces.

Nearly 82% of the world's almonds come from the Golden State. It's also the nation's sole producer of artichokes, figs, olives, walnuts and raisins.

Newsom argued California has been "disproportionately affected" by the tariffs and that's why the state, which has already filed 15 lawsuits against Trump since January, would lead the charge against the levies, which currently are 10% on most countries and 145% on China.

"That's our state of mind," the governor said. "That's why we're asserting ourselves on behalf of 40 million Americans."

The lawsuit challenges Trump's invoking the International Emergency Economic Powers Act to enact the tariffs, arguing the act had never been used for such levies and such powers rest with the US Congress.

The lawsuit cites multiple times from rulings by the US Supreme Court against the Biden administration in its quest to forgive student debt, noting the high court called Biden's manoeuvres a "transformative expansion" of presidential authority.

Newsom said if the Supreme Court is "consistent, then this lawsuit is a lock" for the state.

The act has never been used to issue tariffs by any president, congressional research shows.

While California is the first state to file legal action against the Trump administration over the levies, several other lawsuits filed by small businesses and a civil rights group have similarly challenged Trump's authority on the matter.

Since Trump's inauguration in January, there has been a flurry of announcements on tariffs.

The US president says the import taxes will encourage US consumers to buy more American-made goods, increase the amount of tax raised, and lead to huge levels of investment in the country.

Critics argue that bringing manufacturing back to the US is complicated and could take decades and that the economy will struggle in the meantime.

Trump has also backtracked on many of his announcements.

Just hours after steep levies against roughly 60 of America's trading partners kicked in earlier this month, Trump announced a 90-day pause on those tariffs to all countries except China, in the face of mounting opposition from politicians and the markets.