Rape and abuse victims in women-only refuges face being looked after by biological men after England’s biggest group of women’s shelters decided to review its ban on transgender staff.

The move, which could overturn almost half a century of refuges being run by women for women, was described by some feminists last night as the most significant erosion of female spaces yet.

It comes after the government promised to consult on letting people change sex on demand. Activists insist that “self-declared” transgender women — most of whom retain male organs — should be allowed to enter and work in woman-only spaces.

Justine Greening, the former equalities minister who drove the sex-change reforms, admitted for the first time last night that the concerns of women’s groups must be taken more into account.

She told The Sunday Times she still supported change, but stressed that the government should be “absolutely listening to the voices of women’s groups in all this and their concerns”.

The review of women’s refuges, which is not dependent on any government reform, was agreed last week by the board of the charity Women’s Aid, a federation that oversees more than 300 shelters.

Mary Mason, the board’s interim co-chairwoman, said: “We have agreed to start a review of our whole transgender policy, including the possibility of employment for self-declared transgender women without a gender recognition certificate.”

Describing it as “an extraordinarily difficult discussion,” Mason said the review, by Women’s Aid’s director of services, Nicki Norman, would take three to four months. Another board member, Sarah Forster, confirmed the move.

Prominent feminists expressed concern at the development. “Recent victims of male violence need women-only spaces where they can feel safe from men,” said Stephanie Davies-Arai, of the campaign group Transgender Trend. “This risks retraumatising vulnerable and victimised women for the sake of ideology.”

Karen Ingala Smith, head of the women’s sexual and domestic violence charity NIA, said she was concerned.

“I hope refuge providers protect the ‘for women by women’ vision of the feminist survivors and activists who built the refuge movement.

“A women-only space is one of the ways we can create a sanctuary for women to begin their recovery from men’s violence. Women and children escaping violent men should at the very least be able to expect this of a refuge,” Smith added.

A rape victim who stayed in a Women’s Aid centre said: “I am terrified for other women if this happens. I went through a patch where I feared and could not bear the sight of any man. The wonderful support I got just could not have been provided by staff who, to all intents and purposes, are men.”

Women’s Aid stressed that local refuges would be fully consulted in the review and would still have a say over who they employed.

Refuges already allow trans women as clients, though they are permitted to exclude them on a case-by-case basis. Women’s Aid’s quality standards say its services must be “accessible to transgender women”.

Currently, staff who are on the premises all the time with access to all areas are not employed in refuges without a female birth certificate. All refuge job ads on the Women’s Aid website say the applicant must be a woman.

Only people born female — or who have gone through the Gender Recognition Act process to change sex — can get a woman’s birth certificate. The government promised to consult on making the process easier, but has delayed the consultation amid growing controversy over the issue.

Equalities legislation allows providers of single-sex services to discriminate where this is “a proportionate means of achieving a legitimate aim”.

Women’s groups also fear predatory men could use any change to access shelters. Such cases are rare but in Canada, a sex offender, Christopher Hambrook, posed as trans to obtain entry to shelters and commit attacks. This view was attacked by trans campaigner Sarah Brown, who said it “punishes vulnerable trans women for hypothetical acts of infiltration by men claiming to be trans women”.