The Democratic Alliance and Congress of the People on Saturday both called for Social Development minister Bathabile Dlamini to be sacked immediately following the resignation of her director general.
DA MP Bridget Masango in a statement said Dlamini's influence had become toxic and she can no longer be trusted with delivering the social grants of 17 million people.
"Reports today that Social Development Director General Zane Dangor has resigned is yet another sign of the Social Development Minister's destructive and toxic influence and should see her removed immediately.
"Dlamini has utterly failed to ensure that Sassa was ready to take over the distribution of grants at the end of this month when the current invalid CPS contract comes to an end and has allowed the situation to reach crisis point.
"In fact, she has manufactured this crisis and even misled the Constitutional Court in October last year when she stated that Sassa would be ready to take over the distribution."
Masango said the party would be writing to chairperson of the Portfolio Committee on Social Development, Rosemary Capa, to request that she invite Dangor to come before the committee to detail what has been taking place.
The President has more than enough cause to remove her and for the sake of millions of South Africans, the DA calls on him to do so immediately.
Dangor must come forward - Cope
The Congress of the People meanwhile said there can now be no doubt that the Department of Social Welfare is in a serious crisis, but thought Dlamini would resign before Dangor.
"Cope is very disappointed that Dangor decided to resign before telling the country the whole truth about this whole Sassa saga," party spokesperson Dennis Bloem said on Saturday.
"Cope has expected that Minister Bathabile Dlamini would resign and not Dangor."
They called for Dlamini to tender her resignation for failing to give proper political direction in this "time of uncertainty" for social grant recipients.
They also urged Dangor "not to be a coward and leave in silence", as he owes the country an explanation as to what is really happening with the "untouchable" CPS contract.
The standing committee on public accounts lamented Dangor's resignation earlier on Saturday.
Scopa chairperson Themba Godi said the committee was angry that a "hardworking and honest" director general like Dangor had to resign over the Sassa matter.
Dangor confirmed to News24 on Saturday that he tendered his resignation on Friday.
He said it was essentially a breakdown in the relations between himself and the minister over disagreements on Sassa's legal obligations to the Constitutional Court.
He did not want to comment on whether he thought he had been treated unfairly on the Sassa matter. -- News24