Tesla boss Elon Musk has gone on a Twitter tirade, siding with President Donald Trump and his steel and aluminium tariffs, while taking a shot at China.

Musk, who was a member of President Trump's advisory council prior to leaving it in June 2017, raised the issue of the US-China automotive import and export tariffs by asking the president whether the two countires should have the same rules for cars, according to Fox News.

"Do you think the US and China should have equal and fair rules for cars?" Musk wrote. "Meaning, same import duties, ownership constraints and other factors."

Musk pointed out that American companies that ship their cars to China pay a significantly larger import duty than Chinese cars that come to the US.


"For example, an American car going to China pays 25 per cent import duty, but a Chinese car coming to the US only pays 2.5 per cent, a tenfold difference," Musk tweeted.

Musk said in his Twitter rant that he had raised the issue with the Obama administration, but nothing was ever resolved.

Today Trump signed off on new steel and aluminium trade tariffs that many fear could spark a trade war.

Trump used his executive powers - evoking national security risk - to apply tariffs of 25 per cent on steel and 10 per cent to aluminium but said there would be a 15 day window for nations to make an appeal for exemptions.