Cross-party MPs will meet with the home secretary today to query the government's plans allowing protesters to engage in "silent prayer" and approach women with leaflets inside buffer zones around abortion clinics.
Despite MPs voting over a year ago to ban these activities, draft guidance released by the Home Office now appears to water down the laws, campaigners have said.
"Safe access zones" were meant to be introduced to create a 150m-wide area outside clinics to stop anti-abortion campaigners from handing out leaflets, holding vigils and showing graphic images to women near the sites.
But under draft guidance from the government for councils, police and abortion providers, it appears protesters would still be able to approach vulnerable women seeking treatment on their way into clinics.
Another exception also allows for "silent prayer" within the 150m protection zones.
Labour's Rupa Huq and Conservative Sir Bernard Jenkin - who originally tabled the amendment to the Public Order Act on the issue - are meeting with Home Secretary James Cleverly to discuss the guidance, Sky News understands.
The MPs believe the exceptions in the draft guidance would still amount to the harassment of women who are seeking abortions and that it could risk undermining the original law agreed by parliament.
The Home Office has recently ended a public consultation on the issue and will finalise guidance by the spring.
A spokesperson from the department said: "It is completely unacceptable that anyone should feel harassed or intimidated whilst exercising their legal right to access abortion services.
"We are currently considering all responses to the consultation and final guidance will be published in due course."