The Government could be set to back proposals from Liz Truss that would bar “biological males” from female-only spaces.

Equalities Minister Kemi Badenoch is understood to be sympathetic to proposals from the former prime minister, due to be debated in the Commons on Friday, that would “define sex in law as biological sex”.

The legislation aims to bar transgender women from female-only spaces such as changing rooms and toilets, along with preventing them from competing in women’s sport and stopping children from attempting to change their gender.

But the Cabinet minister is said to regard Ms Truss’s current proposals as “unworkable” and could look to amend them.

A Government aide said: “Kemi is very supportive of the aims of Liz’s Bill but it is unworkable in its current form.

“Nonetheless it can support Kemi’s work on the definition of sex, and colleagues’ work banning puberty blockers, and Liz is keen to help.”

Ms Truss has previously said her Bill would provide a clear dividing line with Labour on what has become one of the main “culture war” issues.

The aide agreed, adding: “The Labour Party is hopelessly split on these issues, so the Conservatives should be open to all ideas to improve protections for women and girls.”

As a backbench Bill, Ms Truss’s proposals are unlikely to become law without Government support, and may not even be debated on Friday as there are two other Bills on the order paper ahead of it.

But the Government is said to be largely sympathetic to her aims, with the Department of Health and Social Care understood to be the final block to accepting the former prime minister’s legislation.

A Whitehall source said: “The Bill has policy consequences which the Government is sympathetic to.

“The only questions which have puzzled ministers is why the MP proposing the Bill did not legislate for the changes when she was minister for women and equalities or when she was prime minister.”

The debate on Ms Truss’s Bill follows the announcement on Tuesday that the NHS will no longer prescribe children puberty blockers, a move welcomed by the Government as being in “the best interests of the child”.

The Government also published draft guidance in December on how schools should support pupils who were questioning their gender, which stated that “parents should not be excluded” from decisions relating to children who want to “socially transition”, for instance by changing names, pronouns or clothing.

Ahead of Friday’s debate, Ms Truss said she was “very much hoping” that the Government would support her Bill, adding: “This would be hugely positive for the protection of children.”

She said: “I have been overwhelmed with supportive messages this week not only from constituents, but from people across the country and indeed all corners of the world who want to see my Bill put into law so that children and women get the protections they need in the face of the extreme agenda being pursued by militant gender ideologues.”