Women's careers are being held back as men in the United States avoid spending time with female colleagues in the wake of the #MeToo movement, women's rights group LeanIn.org said on Friday.

Nearly two thirds of male managers reported they would be uncomfortable taking part in a common one-on-one work activity with a woman, found a survey by the group and SurveyMonkey, a rise of a third on the number raising such concerns last year.

The findings show women miss out on chances for mentorship and professional links that could lead to promotion, they said.

“A lot of men don't realise sitting on the sidelines is actually continuing to limit the opportunities of women,” Rachel Thomas, president of LeanIn.Org, told the Thomson Reuters Foundation.

“This data really shows that we are moving in the wrong direction at a time when it's so critical that women are getting mentorship and sponsorship and equal access.”

The #MeToo movement that swept through social media saw women share stories of sexual abuse and harassment, leading to the firing of some high-profile figures and a wider debate over pay, representation and sexism.

But some suggest it has left men wary of perceived inappropriate conduct or harassment allegations.

Thirty-six per cent of men in the survey of more than 5,000 US adults said they had avoided mentoring or socialising with a woman because they were nervous about how it would look.

Senior level men in particular appeared less willing to spend time with female junior colleagues than their male co-workers at a similar level.

They were 12 times more likely to hesitate to have one-on-one meetings with a junior woman than a man, nine times more likely to have concerns over travelling together and six times more likely to hesitate to have a work dinner with them.

The survey indicated that workplaces are stepping up their misconduct responses, with 70 per cent of employees saying their company has taken action to address sexual harassment a significant increase from 46 per cent in 2018.

However, half of men believed sexual harassment claims were more damaging to careers of the alleged perpetrators than their victims, while nearly two thirds of women said the person making the complaint paid a higher price.

Women's groups said the findings showed the need for more action to ensure equality at work.

“#MeToo helped shine a light on just how prevalent sexual harassment is in the workplace, and laws and policies have not yet caught up with the social awareness around it,” said Shelby Quast, a spokeswomen for women's rights group Equality Now.

"We have to encourage a healthy work environment among all employees and perpetrators need to be held accountable."