Gauteng housing MEC Humphrey Mmemezi's resignation over personal use of a government credit card should set a precedent for others, Cosatu said on Wednesday.

"We note that comrade Mmemezi strenuously denies some of the allegations, but has conceded that others, particularly those relating to the misuse of the credit card, are valid," the Congress of SA Trade Unions said in a statement.

"He is therefore to be congratulated on his honourable decision to resign and to refund government for the improper expenditure."

Mmemezi announced his resignation earlier in the day, saying he had been under the impression that he could make personal purchases on the department's corporate credit card, as long as he repaid the money.

Cosatu said: "We hope that this will set a precedent for other public office bearers who have been accused of similar, and in some cases more serious offences, including corruption or even murder, to step down while the allegations are investigated."

Cosatu only regretted that he took so long to do so, given the damage to the provincial government's reputation.

Spokesman Patrick Craven said it was "absolutely unacceptable" that public representatives could continue to hold positions in government while facing investigation or criminal prosecution.

"And even mobilise demonstrations of support outside the courts where they are standing trial," he said.

Craven said Mmemezi's defence relating to his understanding of the use of the card supported the federation's call for a review of the Ministerial Handbook. It needed to unambiguously spell out rules for the use of public money.