The KwaZulu-Natal ANC Women's League on Friday dismissed MP Makhosi Khoza's attacks on the party as "nothing new'.
"Her opportunistic behaviour to collude with organisations formed by individuals who left the movement under a cloud in their agenda to remove the ANC from power is a clear indication that she has now completely lost it," the league said in a statement.
The organisation, established to promote women's rights, said it was unfortunate that Khoza was making the comments against her "a gender-based matter".
Khoza has pointed out that while she has been criticised for speaking out against the ANC and its leaders, other party members, including former finance minister Pravin Gordhan, have not.
"Women appear to have a different justice system in the ANC as so many ANC leaders have spoken publically against the president.
Well, am I being disciplined for occupying my legitimate seat in an equal society?" she wrote in a Facebook post on Thursday.
Khoza on Tuesday called on President Jacob Zuma to resign. He was promoting tribalism, which was evident in a society that was divided along racial lines.
She was speaking at the Conference for the Future of South Africa in Johannesburg, organised by Save SA.
"Please save South Africa, save jobs, Mr President, save the economy and save women. I cannot even say more about how much you have violated the country's Constitution," she said to applause from the audience.
On Wednesday, the ANC in KwaZulu-Natal said she had crossed the line and it would take disciplinary action against her.
ANC Chief Whip Jackson Mthembu previously accused her of "extreme ill-discipline" after she publicly criticised what she called the politics of patronage.
In her Facebook post on Thursday, Khoza said she refused to "die silently". She had received death threats for her criticism of Zuma.
"I have been singled out as a troublemaker by those that would have me go quiet. I have been accused of extreme ill-discipline for standing for what I believe.
"Why should I die silently? Why should my body be added to those who have died innocently and keep quiet about it?
Many of my comrades died while remaining silent, many of my comrades will die silently still, [especially as December approaches] yet those who accuse me have done nothing about it," she said.