Interim guidance on single-sex spaces is “ill-considered and impractical” and should be withdrawn, the Green Party has said.

The guidance, issued by the Equality and Human Rights Commission (EHRC), followed the UK Supreme Court’s ruling that a woman is defined by biological sex under the Equality Act.

In places like hospitals, shops and restaurants, trans women (biological men) should not be permitted to use women’s facilities but they should not be left with no facilities to use, the guidance says.

Green Party co-leader Carla Denyer told the BBC the guidance puts trans people at risk of discrimination, while Lib Dem leader Sir Ed Davey said there were questions over enforcement.

The UK government has welcomed the Supreme Court ruling, saying it brings “clarity” for women and service providers.

A spokesperson added: “We will review and update policy wherever necessary to ensure it complies with the latest legal requirements.”

The EHRC, which enforces equalities law and provides guidance to policymakers, public sector bodies and businesses, has been approached for comment.

Last week the Supreme Court found the terms “woman” and “sex” in the 2010 Equality Act “refer to a biological woman and biological sex”.

This means, for instance, that transgender women, who are biologically male but identify as women, can be excluded from women-only spaces.

As part of the judgement in the case brought against Scottish ministers by the group For Women Scotland, Supreme Court judge Lord Hodge stressed that the law still gives protection against discrimination to transgender people.

Carla Denyer, co-leader of the Green Party of England and Wales, said the interim guidance, which was published on Friday following the Supreme Court ruling on 15 April, was “rushed and ill-thought out”.

“It’s been really obvious that they have not listened to trans people,” she told BBC One’s Sunday with Laura Kuenssberg programme.

She added that the guidance put trans people at risk of discrimination, especially in workplaces, and “seems to fly in face of the strong tradition of tolerance we have in Britain”.

The Green Party said in a statement that the guidance was likely to cause “distress” to the trans community as well as “further confusion to employers, businesses and service providers” .

It is calling for the guidance to be withdrawn “until the EHRC can produce something more thought-through which takes into account the voices of all those affected”.

Denyer questioned what should happen if trans people are not allowed to go to the toilet of their gender or their birth sex.

The guidance also states that in some circumstances the law allows trans women (biological men) not to be permitted to use men’s facilities, and trans men (biological women) not to be permitted to use women’s facilities.

When asked to clarify this, the EHRC pointed to a section of the Supreme Court ruling stating that trans men could be excluded from women’s facilities “where reasonable objection is taken to their presence, for example because the gender reassignment process has given them a masculine appearance or attributes to which reasonable objection might be taken” in the context of a women-only service.

However, the guidance says where possible mixed-sex toilets or changing facilities should be provided, with lockable rooms intended to be used by one person at a time, in addition to single-sex facilities.

Denyer also raised concerns that for lesbian associations or venues which wanted to include trans women, the advice appeared to say they would not be allowed to.

The guidance states that women-only or lesbian-only associations “should not” admit trans women, while men-only or gay men-only associations “should not” admit trans men.

Sir Ed also told the programme lots of people were confused and anxious about the guidance, for example over which toilet a trans man (biological woman) should use.

The Lib Dem leader said his party accepted the Supreme Court ruling but there needed to be more debate in Parliament to reach a clear solution that “respects people’s rights”.

Cabinet Office minister Pat McFadden said the “logical consequence” of the Supreme Court ruling and EHRC guidance was that “people use the facilities of their biological sex”.

Asked if the government would ban trans people from using changing rooms or toilets they wish to use in its own buildings, he told the BBC: “In reality, when you say ban, am I going to be standing outside toilets? I’m probably not.

“There isn’t going to be toilet police but that is the logical consequence of the court ruling and the EHRC guidance.”

The EHRC is expected to launch a two-week consultation to seek views from those affected by the guidance in May.

The watchdog is then aiming to provide an updated code of practice to the government for ministerial approval by the end of June.