Cosatu on Wednesday welcomed Mbhazima Shilowa's resignation as Gauteng premier, calling him a hypocrite whose public support for ousted president Thabo Mbeki was "unbecoming".

"We are of the view that the premier's resignation was expected, given his loyalty to former president Thabo Mbeki, rather than to the ANC that elected him...

"He [Shilowa] is one of the biggest hypocrites of our time," the Congress of SA Trade Unions said in a statement.

Shilowa is a former secretary general of the trade union movement.

Cosatu said it was "unacceptable" that Shilowa said he would find it difficult to defend the decision of the national executive committee of the ANC to remove Mbeki from office.

"We are not taking kindly his continuous criticism of that decision to recall Thabo Mbeki... He does not have any authority to lambaste the ANC NEC decision in public," it added.

The trade union movement traced past comments by Shilowa as far back as 1999, when he, according to the statement, said he would "make mincemeat of Cosatu if it ever makes his life difficult as premier".

Cosatu said he should leave office immediately and not at the end of October. "We believe that we can't entrust ill-disciplined cadres with the responsibility of being the guardians of the state resources."

The ANC provincial executive committee will nominate three candidates on Wednesday to take over from Shilowa.

Sapa