Deputy President Kgalema Motlanthe's request to have Public Protector Thuli Madonsela investigate bribery allegations made against his partner was welcomed on Tuesday.
The Council for the Advancement of the SA Constitution (Casac) said Motlanthe demonstrated "openness and accountability".
"Motlanthe has treated the allegations with the seriousness it deserves and has acted in the spirit of the Red Card Corruption campaign that seeks to entrench a zero tolerance approach to corruption," Casac chairman Sipho Pityana said in a statement.
Pityana said he hoped Madonsela would investigate the allegations against Motlanthe's partner Gugu Mtshali.
According to a report in this weekend's Sunday Times, Mtshali had allegedly been involved in soliciting a R104 million bribe from a South African aviation company, in exchange for government support.
This was part of a R2 billion deal that involved selling US-made helicopters to Iran, via South Africa, in violation of UN sanctions.
Mtshali, former De Beers executive Raisaka Masebelanga and others allegedly met representatives of 360 Aviation to solicit the bribe.
The Sunday Times claimed to have an audio recording of the meeting, on which Mtshali's voice was allegedly heard. The alleged deal reportedly failed because 360 Aviation could not reach an agreement with the National Iranian Oil Company.
Motlanthe has asked the Public Protector Thuli Madonsela to investigate.
Earlier, Madonsela's spokeswoman Kgalalelo Masibi said the protector was assessing whether she had jurisdiction to investigate the allegations.
"She is not investigating, she is assessing the request," Masibi said.
The Congress of SA Trade Unions applauded Motlanthe for approaching Madonsela.
"We consider this action on the part of the Deputy President as exemplary of a leadership that is willing to subject itself to public scrutiny and
accountability," Cosatu spokesman Patrick Craven said in a statement.
He said relatives of public representatives and trade unions should not do any business with the government to avoid a conflict.
"Without speculating about Ms Mtshali's guilt or innocence, Cosatu wishes to state that such reports vindicate our long held position about relations between business and government leaders," said Craven.
Motlanthe's office released a statement at the weekend, which read: "Both Deputy President Motlanthe and Ms Mtshali are firmly of the view that they have committed no wrongdoing of any kind in relation to the alleged events described in the Sunday Times story."
Motlanthe's office said the allegations were serious and needed investigation.
"Having regard to the serious nature of the allegations and imputations of the story, Deputy President Motlanthe is of the view that the issues should be subject to an investigation by the Public Protector.
The deputy president and Ms Mtshali will make themselves available to provide any information to the Public Protector should she decide to investigate the allegations."