The long-time host of hit US dating shows The Bachelor has said he is stepping aside after widespread criticism of his comments on race.

Chris Harrison drew ire after he excused behaviour of a current cast member that some said was racist, saying he was not the "woke police".

"By excusing historical racism, I defended it," the 49-year-old host said in an Instagram post announcement.

This current season is the first to feature a black lead.

The show revolves around a single bachelor selecting a potential spouse from a pool of hopefuls.

In June 2020, fans of the ABC show petitioned for it to address the unequal treatment of cast members of colour.

At the forefront of that initiative was Rachel Lindsay, who at the time was the only black lead to have ever served on The Bachelor's sister show, The Bachelorette.

The show responded with a promise to address their race issues by casting more people of colour. They announced the first black lead, Matt James, as the next Bachelor on 12 June 2020, following the protests over George Floyd's death.

When pictures surfaced of current contestant Rachael Kirkonnell at an Old South fraternity formal at a former slave plantation in 2018, she drew immediate criticism from fans. Ms Kirkonnell has since apologised.

In an interview with Mrs Lindsey on Extra TV, Mr Harrison defended Ms Kirkonnell, a current front-runner who has yet to be eliminated from the show.

"I saw a picture of her at a sorority party five years ago and that's it," said Mr Harrison. Ms Lindsay reminded him the photo had been taken in 2018, which "wasn't a good look".

"Well, Rachel, is it a good look in 2018? Or, is it not a good look in 2021? Because there's a big difference," said Mr Harrison.

To this, Mrs Lindsay pushed back and said: "It's not a good look ever."

"I am not the woke police," he replied, a phrase he reiterated several times throughout the interview.

After the interview went live on Tuesday, a petition for the network to fire him went viral. By Saturday morning, it had amassed 38,000 signatures.

Mrs Lindsay, who met her now-husband on the show, addressed her 13-minute interview with Mr Harrison on a podcast she hosts on Friday.

"During that conversation, he talked over me and at me, during that conversation," she said.

"He never gave me room to talk. And he never gave me room to share my perspective. He wasn't trying to hear it. He was just trying to be heard."

Over the next few days, fans pressured former cast members to speak out.

Ben Higgins and Joelle Fletcher, both good friends of Mr Harrison and considered frontrunners to succeed him should he eventually retire, condemned his words.

"Chris' statements were harmful. They were not helpful," Mr Higgins wrote on Instagram.

The momentum snowballed as the entire cast from this season posted a joint statement standing by Mrs Lindsey.

Although Mr Harrison issued an initial apology on Thursday it was not satisfactory for many members of Bachelor Nation, the self-proclaimed name given to fans of the show, and the number of people petitioning for his firing grew.

After two days of silence, he announced on Saturday he would be taking a step back "for a period of time".

"To the Black community, to the BIPOC community: I am so sorry. My words were harmful," he said on Instagram.

Mr James' season is just over halfway and has already been filmed, so Mr Harrison will not be absent from viewers' screens just yet.