Bernie Sanders has hit Republican presidential hopeful Nikki Haleys proposal that politicians over 75 should be given a mental competency test – calls it “absurd”.

Haley, 51, made the claim as she launched her campaign to win the GOP nomination, criticizing the 76-year-old Donald Trump and 80-year-old Joe Biden.

But Mr Sanders, who is 81 himself, rejected the idea when he appeared CBS Face the Nation on Sunday morning.

“I think it’s absurd. We fight racism, we fight sexism, we fight homophobia, I think we should also fight ageism. said the US senator from Vermont.

“Trust people, look at people and say, ‘You know, this person is competent, this person is not competent.’

“There are a lot of 40-year-olds out there who are not very competent. Older people, you know, you look at the individual, I don’t think you’re making a blanket statement.”

Meanwhile, Haley, a former governor of South Carolina and Mr Trump’s pick for US ambassador to the United Nations, was asked why she would be the Republican nomination as she appeared on Fox News Sunday.

“Why not me?” she answered. “You know, I’m the wife of a combat veteran. I’m the mother of two.”

And again called for term limits in American politics.

“And what I strongly believe is that the American people need alternatives. I don’t think you have to be 80 years old to be in Washington DC,” she said.