Indian-American Republican presidential candidate Nikki Haley has challenged her ex-boss and former president Donald Trump on to a debate stage and vowed to stay in the race after losing the party's New Hampshire primary.

Haley, 52, has attacked Trump, 77, and questioned his "mental competency".

“The other day, Donald Trump accused me of not providing security at the Capitol on January 6th. I’ve long called for mental competency tests for politicians over the age of 75. Trump claims he’d do better than me on one of those tests. Maybe he would, and maybe he wouldn’t. But if he thinks that, then he should have no problem standing on a debate stage with me!” Haley said in her speech after the results started coming in.

On Tuesday, Trump won the New Hampshire Republican presidential primary with 53.1 per cent of the votes and Indian-American Haley trailed with 45.8 per cent when over 40 per cent of the votes polled were counted.

Haley performed better than expected but she lost to Trump. The Republican primary now moves to South Carolina, the home State of Nikki Haley. However, Trump is polling ahead of Haley.

Haley told her supporters that with Trump, Republicans have lost almost every competitive election.

“We lost the Senate. We lost the House. We lost the White House. We lost in 2018, in 2020 and in 2022. The worst-kept secret in politics is how badly the Democrats want to run against Trump. They know Trump is the only Republican in the country who Biden can defeat,” she said.

“You can’t fix the mess if you don’t win the election. A Trump nomination is a Biden win and a Kamala Harris presidency. I defeat Biden handily,” she claimed.

“With Donald Trump, you have one bout of chaos after another. This court case, that controversy, this tweet, that senior moment. You can’t fix Joe Biden’s chaos with Republican chaos,” she said.

“But if he thinks that, then he should have no problem standing on a debate stage with me! Most Americans do not want a rematch between Biden and Trump. The first party to retire its 80-year-old candidate is going to win this election. I say it should be the Republicans! So our fight is not over, because we have a country to save,” Haley said.

Haley said in the next two months, millions of voters in over twenty states will have their say.

“We should honour them and allow them to vote. And guess what, in the next two months, Joe Biden isn’t going to get any younger or any better. We’ll have all the time we need to beat Biden,” she said.

In his speech, Trump told his supporters that Haley would never get the nomination and if she did, she would be under investigation.

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