Rebecca Long-Bailey, Angela Rayner and Dawn Butler have backed a new trans rights charter that calls on Labour to expel “transphobic” members and describes campaigns including Woman’s Place UK as “trans-exclusionist hate groups”.

A row broke out over the endorsements after Long-Bailey, a leadership candidate, as well as two deputy hopefuls, Rayner and Butler, all expressed support for the Labour Campaign for Trans Rights’ 12-point pledge card.

Lisa Nandy, another Labour leadership candidate, tweeted her support for the Labour Campaign for Trans Rights without specifically endorsing the pledge card.

The charter calls on signatories to “organise and fight against transphobic organisations such as Woman’s Place UK, LGB Alliance and other trans-exclusionist hate groups”.

It was launched this week with a warning from the Labour Campaign for Trans Rights that the party had “failed to act as transphobia has gained ground” within Labour, despite the party’s manifesto supporting trans equality and gender recognition”.

However, the endorsements from leadership candidates have angered campaigners for Woman’s Place UK, which has been pushing for the government to consult more widely about changes to the Gender Recognition Act that would allow people to legally self-identify as a man or a woman without medical approval

Leading members of Woman’s Place UK - Ruth Serwotka, Judith Green and Kiri Tunks – called on the candidates to withdraw their support for the card and challenged Labour to “defend us or expel us”. They also rejected the charge that their group was transphobic and trans-exclusionist, saying such claims were defamatory.

Critics of Woman’s Place UK argue that the campaign seeks to limit trans people’s rights and dismisses the validity of some trans people’s gender identity.

The Labour Campaign for Trans Rights said it was “heartened by the solidarity” of the Labour candidates, and in relation to Woman’s Place UK the “evidence is clear of the discrimination trans people suffer from in our society, and organisations like theirs exist to perpetuate that discrimination. It’s our view that bigotry has no place in the Labour movement, including transphobic bigotry.”

It added: “We also want to emphasise that the response to our campaign has been overwhelmingly positive outside what is a small group of transphobes. We have now over 3,000 signatures to our pledges in just two days, representing a huge amount of support from the Labour party as a whole.”

Transgender activists have also criticised the LGB Alliance as transphobic. When the group launched in October last year, founding member Allison Bailey said “gender extremism is about to meet its match”. Bailey has also warned of the dangers posed by the “international, all-powerful, wealthy & totally out of control trans lobby”.

The group rejects claims of transphobia, insisting that “pseudo-scientific” approaches to gender are putting the rights of gay and bisexual people at risk.

Serwotka, Green and Tunks all deny that their organisation is transphobic, releasing a statement on Tuesday saying their campaign was established to “ensure that women’s voices are heard and our sex-based rights upheld”.

“We are extremely concerned by the scurrilous mischaracterisation of Woman’s Place UK as a ‘transphobic organisation’ and a ‘hate group’ by some individuals and groups in the Labour party, including leading figures in the current leadership election,” they said. “These are accusations we absolutely refute and which we believe to be defamatory.

“We call on those making such accusations against us to provide evidence for these claims or withdraw them.”

Sam Smethers, the chief executive of the Fawcett Society, said: “Trans people are targeted with violence, abuse and threats and so are women who speak out about the need to defend women-only spaces and sex-based rights. Women’s fear of male violence is real and justified.

“For reasons of women’s privacy, dignity and safety the need for single-sex spaces remains. But trans people’s human rights must also be recognised and their needs must also be met. The only way forward is for both sides of this issue to be heard with mutual respect. Characterising Women’s Place UK in this way misrepresents them and is fundamentally unhelpful. It is time to move this agenda forward.”

The Woman’s Place UK campaign was set up in 2017 to call on the government to consult more widely about how changes to the Gender Recognition Act would affect women if ministers pressed ahead with plans to allow people to self-identify as a man or a woman. It claims that changes to self-identification are likely to threaten the rights of women. Critics view its stance on a range of issues as coming into conflict with the rights of trans people.

The government has delayed publication of its long-awaited decision on changes to the Gender Recognition Act, but it is expected to make a call on whether to push ahead with allowing people to legally self-identify their gender as soon as next month. Liz Truss, the trade secretary and women’s and equalities minister, is leading on the policy.