Woman's Place UK campaigns for women-only spaces and raises concerns about transgender people being able to self-identify as women.
The social network temporarily blocked links to its website over the weekend citing user "safety" as the site was "malicious".
"This morning, our supporters are reporting that FB posts which link to our website are being removed," tweeted the group, "the reason give (sic!) is that 'they may be in breach of community standards'. They are not. We would urge you to visit our website, read the posts and decide for yourself".
Its supporters blasted Facebook's clampdown, calling it a "disgrace" and accused the site of "suppressing free speech".
"Only fake news and hard brexit is allowed on @facebook. Women's rights are bad, m'kay." tweeted one user.
The move coincided with a Twitter post from user @mimmymum, whose profile indicates the account belongs to Helen, who is "passionate about acceptance for transgender people & #trans kids".
The tweet included screenshots prompting users to report Woman's Place UK's group to Facebook for breaching its guidelines.
Helen also accused it of transphobia and excluding trans women.
Comment: Now we're all getting a small taste of what it was like living in the Soviet Union. You stand accused.
Judith Green, of Woman's Place UK, told The Times it was difficult to contact Facebook to discuss why it had blocked the links, adding: "We regard it as a fairly serious interference in democratic discussion. This is about women's voices being able to be heard".
Woman's Place UK was formed in September 2017 in the wake of the government's pledge to amend the Gender Recognition Act, allowing people to legally change their gender without medical approval.
The group says it wants a "respectful and evidence-based discussion about the impact of the proposed changes to the Gender Recognition Act to be allowed to take place and for women's voices to be heard".
It has accused social media sites of deliberately "obstructing" and "hiding" its posts and alleged that its detractors are setting up fake profiles as part of a smear campaign against its nationwide events and public meetings.
Facebook's crackdown, and subsequent u-turn, is the latest in a series of gaffes for the company.
Just days ago, Facebook boss Mark Zuckerberg backtracked from his apparent defence of holocaust deniers on his site.
"I don't think that they're intentionally getting it wrong," the 34-year-old tech mogul originally said of the conspiracy theorists.
Comment: The thing is, he was right. Most Holocaust deniers don't think they're intentionally getting it wrong - they think they're right - whether the are or not. If people can believe flat earth theories, they can believe Holocaust denial theories.
A backlash swiftly followed that forced the multi-billionaire to clarify his controversial remarks.
"I personally find Holocaust denial deeply offensive, and I absolutely didn't intend to defend the intent of people who deny that," Zuckerberg wrote in a follow-up note.
But Facebook's policy allowing such blatant misinformation remains unchanged.
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