US President Donald Trump wants a 20 per cent border tax on all imports from Mexico, White House spokesman Sean Spicer has said.

Spicer on Thursday said Trump wanted to use the new tax to fund the proposing wall between the US and Mexico, Xinhua news agency reported.

Spicer said this hours after Mexican President Enrique Pena Nieto cancelled the work meeting with President Trump scheduled for next Tuesday in Washington.

Spicer didn't release any detail about how the new tax will work.

Building a wall at the US southern border with Mexico to be paid by Mexico was one of Trump's key election campaign pledges. Trump signed an executive order on Wednesday to build "a large physical barrier" between the two countries.

Trump reiterated on Wednesday during an interview that the wall project will start as soon as possible and financed by Washington, but Mexico will "100 per cent" reimburse the US at "a later date," which has been rejected by Mexican government several times.