Ministers have been warned it would be "shameful" if they backtrack on a shake-up of sexual harassment laws in the workplace.
The Tories are reportedly set to stop a bill which would make employers liable for harassment by "third parties" - such as customers.
It follows a backlash from senior Conservatives, with controversial chat show host Jacob Rees-Mogg among its critics.
The Worker Protection Bill, put forward by Lib Dem Wera Hobhouse, would introduce a requirement for companies to take “all reasonable steps” to prevent harassment of staff.
But critics claim it will create issues for employers, with former cabinet minister Lord Frost dismissing it as a “woke, socialist measure” which he claims would “have a chilling effect on every conversation in a workplace”.
Tory peers are set to block it by tabling a series of amendments which means it will not pass by the end of the Parliamentary session, The Telegraph reports.
Labour deputy leader Angela Rayner said: "Tory Ministers stood up in Parliament, backed this new law & said it would be 'an important step change in the protections available against workplace harassment'.
"But now they’re turning their backs on women experiencing sexual assault at work. Yet another Tory broken promise."
It was also criticised by TUC General Secretary Paul Nowak, who said: “It would be utterly shameful if the government allows this bill to fall.
“Ministers promised to bring in new laws to tackle sexual harassment. But now appear to be backsliding.
“Let’s not forget - women are experiencing sexual harassment and abuse on an industrial scale.
“And we know many in public-facing jobs - like shop workers and GP receptionists - suffer abuse and harassment regularly from clients and customers.
“Rishi Sunak must not abandon vulnerable staff. These protections are essential.”
Following reports that her bill will be prevented from passing, Ms Hobhouse said: “If the Government allows this Bill to be ‘timed out’, it would be a betrayal to those who face sexual harassment in the workplace.
“Whenever I present legislation that will act to protect women from horrifying sexual offences, Rishi Sunak’s Conservative Party present a roadblock.
“This Government’s unfounded and overblown concerns leave women without safeguards. It is a shameful set of circumstances when they decide not to implement transformative legislation for vulnerable workers.”
A Tory source told The Telegraph: “Ultimately, this Bill will be timed out."
They added: “It’s worth going away and thinking again how we can achieve what we wanted to achieve with this Bill, but in a way that doesn’t have the unintended consequences that colleagues have flagged as being a concern.”
Mr Rees-Mogg said he was against the bill as employers "have too many burdens already".