The government must stop applying the so-called "bedroom tax" to domestic abuse survivors fleeing their partners, 44 MPs have written in a letter seen by the BBC's Victoria Derbyshire show.
One rape survivor, living in a home adapted for her safety, had her housing benefits cut because of her spare room.
The European Court of Human Rights said her case was discriminatory. A government bid to appeal was refused.
The government said it was "carefully considering" the court's decision.
The MPs - from all the major political parties in Westminster - said vulnerable women "must not be forced out" of the safe houses, provided by the UK's Sanctuary Scheme, by the policy.
The letter said 281 households in the scheme were currently subject to such "penalties".
The woman - who is preserving her right to anonymity - is a victim of rape, assault, harassment and stalking at the hands of an ex-partner, her lawyers said.
She was given specially-adapted social housing designed to enable women and children at serious risk of domestic violence to live safely.
The property included a panic space and extra security measures, her lawyers added.
But because the house - occupied by the woman and her young son - was three-bedroomed, it led to a 14% cut in housing benefits - as she was only entitled to receive housing benefit for a two-bedroom property.
After a six-year legal battle, the UK government was ordered by the European Court of Human Rights (ECHR) to pay the woman 10,000 euros (£8,600) in compensation. The court found the policy had unlawfully discriminated against her.
The woman told the Victoria Derbyshire programme: "The constant worry about whether we would be made to leave our home... has been truly awful.
"It's made me anxious not only about money, but also has reminded me of the terrible violence I experienced and had thought I was safe from.
"I am so relieved to know that hopefully my battle is nearly over."
The Department for Work and Pensions sought to appeal against the decision, but had its application rejected.
'Life and death matter'
Now 44 MPs have written to Work and Pensions Secretary Therese Coffey urging her "to take immediate action on this life and death matter".
"The government has committed to improving protection and support for survivors through the new domestic abuse bill," the open letter - coordinated by Labour MP Stella Creasy and supported by charity Women's Aid - said.
"The application of the 'bedroom tax' to Sanctuary Schemes clearly undermines this aim.
"So too, seeking to encourage people to leave their homes for smaller ones as this policy does, is also in conflict with the aim of Sanctuary Schemes - which are designed to enable those at risk of domestic violence to remain in their homes safely.
"We call on the government to act now and create an exemption for this very vulnerable group."
It added that exemptions were already in place for other groups, including disabled siblings who need their own bedrooms, foster carers and households with overnight carers for disabled people.
The government said there were no plans to abolish its policy on the removal of the spare room subsidy.
It said the policy helped contain "growing housing benefit expenditure", strengthens work incentives and makes better use of available social housing.