Welsh Rugby Union (WRU) boss Steve Phillips should resign, the Welsh government's former national adviser for violence against women has said.
Rhian Bowen Davies said his apology was "not enough", adding he "should take responsibility" for what had happened.
"There needs to be urgent steps taken and one of the biggest steps would for him to resign," she said.
It comes after major Welsh rugby sponsors and politicians expressed concern at the allegations.
Principality Building Society, which supports grassroots rugby and sponsors Wales' national stadium, said the allegations were "extremely concerning" and called for "immediate and decisive" action.
Claims were made by an ex-Wales women's manager and a former chairwoman of the Welsh Rugby Union's professional board.
Rhian Bowen Davies was appointed the Welsh government's first national adviser for violence against women, domestic abuse and sexual violence in 2015.
Ms Bowen Davies, who is now an independent consultant in that field, told the S4C Newyddion programme: "Even though I understand that this happened before he came into the role, the culture is something that has strong roots within the union and someone needs to take responsibility.
"This is another example where misogyny and sexism is systemic and is a culture that tries to quieten individuals who suffer any kind of violence or violence at home.
"We need to take definite steps to change this kind of culture. This culture exists in systems where men have ruled for decades."
Meanwhile, First Minister Mark Drakeford said rugby bosses had to take "urgent and transparent action" and acknowledge the scale of the issue to restore confidence in the WRU at question time in the Senedd.
He added the Welsh government would "continue to be in a challenging, where necessary, conversation with them to make sure that a future is set out for the Welsh Rugby Union that commands the confidence of all of those who are players of the game and who want to see it have a successful future".
Admiral, another WRU partner, said in a statement: "Our culture is of paramount importance to us, so naturally the cultures of the partners we work with are also important. While this is a matter for the WRU, given the serious nature of the allegations made, we have and will remain in discussion with them."
And Vodafone, which sponsors Welsh women's rugby, said in a statement it was "concerned about the nature of the allegations made and are in regular communication with the WRU".
It added: "At Vodafone we believe that sport can be a force for good, and through our partnerships we seek to make a positive and progressive difference to fans and wider communities."
Welsh women's rugby ex-manager Charlotte Wathan described a "toxic culture" of sexism at the WRU.
She also said a male colleague had said in front of others in an office that he wanted to "rape" her.
Another female former WRU employee, a mother of one, said she wrote a manual for her husband in case she killed herself.
Since those allegations were made, Amanda Blanc, now chief executive of insurance company Aviva, has come forward to say she told the WRU it had a "deep rooted" culture and behavioural problems and that a union-commissioned review into the women's game was "beyond disappointing" and verged on "insulting to women".
The allegations prompted Principality to speak out.
Vicky Wales, its chief customer officer, said: "Principality Building Society takes great pride in supporting grassroots rugby within the diverse communities we serve, as we have for over 20 years.
"Principality wants to work with partners who share our values.
"The allegations in the emerging BBC investigation are extremely concerning and we would expect the WRU to take the immediate and decisive action required to remove any discriminatory and bullying behaviours and to uphold the inclusive values that we should all live by."
The Welsh Conservative leader Andrew RT Davies said the Senedd's sports committee should consider how it can support "those on the receiving end of this treatment" and work with the WRU to introduce safeguards.
The WRU has also resisted calls to publish its 2021 review of the the women's game in Wales but extracts of it have been seen by BBC Wales Investigates.
In it, past players described Welsh rugby's culture as toxic and called for an end to "inequality" and "empty promises".
The WRU said both cases in the programme were investigated and proper procedures were followed.
The WRU has previously spoken of its commitment to the women's game and last year gave Wales' women players professional contracts for the first time.
The Senedd's sport and culture committee called the accusations "extremely serious".
It said: "The committee expects the WRU to address these issues immediately."
S4C, an official WRU broadcast partner, declined to comment.
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- UNDER THE SPOTLIGHT: Wales Investigates examines the culture within the WRU
- LEGENDS OF WELSH SPORT: Some of the greatest and most inspiring stories in Welsh football