Donald Trump never fails to take an opportunity to rail against the Obama administration or the deals it cuts with other nations.

But his language reached a new level over the weekend when he accused China of “raping” the United States through its trade policy.

Campaigning in Indiana ahead of a primary contest on Tuesday, he told supporters that China was responsible for “the greatest theft in the history of the world”. He said its manipulation of its currency to make its exports cheaper, was damaging American workers and businesses.

Mr Trump was speaking in Fort Wayne (AP)

“We can’t continue to allow China to rape our country, and that's what we're doing,” he told the campaign rally on Sunday.

“We’re going to turn it around, and we have the cards, don't forget it. We have a lot of power with China.”

Speaking in Fort Wayne, Mr Trump said he was not “angry at China”, but with US leaders who he said were “grossly incompetent”.

Mr Trump, in his campaign manifesto, has pledged to “cut a better deal with China that helps American businesses and workers compete”.

He set out four goals that include immediately declaring China “a currency manipulator” and putting “an end to China's illegal export subsidies and lax labour and environmental standards”.

Latest figures from the US government show the trade deficit with China reached an all-time high of $365.7bn ast year. By February this year, it had already reached $57bn, the BBC reported.

There was no immediate response from Beijing to Mr Trump’s comments.

Ted Cruz has said he has to win in Indiana (Gabrielle Lurie/Getty)

Last week, the US Treasury placed China and others on a currency watchlist, after pressure on the US government to be more robust in combating any currency manipulation by trading partners.

The Treasury stated that none of its large trading partners had engaged in currency manipulation in the past year, but indicated it was concerned about growing imbalances with some of those partners, including China.

Mr Trump’s use of the rape analogy come as Trump is under fire for remarks he made about Democratic frontrunner Hillary Clinton that critics have said were sexist and for boasting about the endorsement of boxer Mike Tyson, who was convicted of rape in Indiana.

This is the first time Mr Trump has used the word “rape” in the context of China and trade, but his campaign for the Republican Party's presidential nomination has been punctuated by inflammatory comments. He was confronted by hundreds of protesters in California on Friday before giving a speech to the state's Republican convention. Mr Trump was forced to enter the building by the back entrance.

Protesters were angry at his views on immigration: he has advocated building a border wall with Mexico, and has also referred to Mexicans as “rapists and murderers” and criminals responsible for bringing illegal drugs into the US.