FORMER US PRESIDENTIAL hopeful Bernie Sanders has apologised for “unacceptable” sexual harassment that occurred during his 2016 campaign.

It was the first time the senator directly addressed an issue that could weigh on his potential 2020 White House bid.

Sanders has been on the defensive for weeks while he mulls another bid, following allegations from several former campaign staffers of sexual misconduct and pay disparity.

“It now appears that as part of our campaign there were some women who were harassed or mistreated. I thank them, from the bottom of my heart, for speaking out,” Sanders said in a statement.

Sanders does not stand accused of harassing staffers himself, but has been criticised for poorly handling the complaints.

The harassment allegations “speak to unacceptable behaviour that must not be tolerated in any campaign or any workplace,” he said.

“To the women in that campaign who were harassed or mistreated I apologise. Our standards and safeguards were inadequate.”

Sanders had apologised before, but not in such a comprehensive fashion.

Thursday’s statement emerged hours after a Politico story that detailed new accusations against a top Sanders adviser who is already taking steps towards working on a possible 2020 Sanders campaign in early voting states like Iowa.

An unnamed woman accused the aide, Robert Becker, of forcibly kissing her shortly after the Democratic National Convention in July 2016.

“This can’t happen in 2020,” the woman said in Politico. “You can’t run for president of the United States unless you acknowledge that every campaign demands a safe work environment for every employee and volunteer.”

The Sanders situation hit headlines after November’s midterm elections, in which the #MeToo women’s movement – propelled by female voters’ frustration with President Donald Trump, who himself stands accused of assault or harassment by multiple women – helped sweep Democrats to victory.

But that same anti-harassment drive that recently brought many men to account for their sexist behavior may ensnare some Democratic potential 2020 candidates.

Sanders, 77, is an independent who ran for the Democratic nomination in 2016.

- © AFP 2019