The minister of foreign affairs has called for her ex-husband to receive a fair trial, as the disgraced former deputy president prepares a legal challenge to last week's dramatic raids by the Scorpions.

"Our foreign policy is that everybody in the world must have a free and fair trial, irrespective of who he is, irrespective of where he is," Nkosazana Dlamini-Zuma told Cape Town students on Tuesday night.

If Jacob Zuma wins, it could put the state's case in jeopardy - the Scorpions would not be able to use seized documents against him in his corruption trial.

Equally, his lawyers are then likely to argue that Zuma's right to a fair trial has been compromised.

After a four-hour meeting with Zuma on Tuesday night, the former deputy president's lawyer, Michael Hulley, confirmed he would file papers in court "as early as next week" challenging the warrants and the legality of the raids.

"The search and seizure has far-reaching implications for the general conduct of the trial, which includes aspects of fairness.

"This is about principles - not about actual documents," he said.

Zuma faces corruption charges, and the elite Scorpions investigation unit is looking into further charges relating to his tax returns and declarations to parliament.

Meanwhile, in an apparent about-turn, Cosatu's leaders were due to admit to the African National Congress on Wednesday that they had lost control and given in to their members' "emotions, beliefs, moods, anger and perceptions" in demanding that Zuma be reinstated as deputy president and that charges against him be withdrawn.

Cosatu general secretary Zwelinzima Vavi and his deputy, Bheki Ntshalintshali, conceded on Tuesday that they had pandered to the pressure of their members and that they might be wrong.

At Wednesday's alliance meeting, Vavi was to use Cosatu members' anger as leverage to unleash a subtle ultimatum that he uttered on Tuesday - that "if this matter is not properly handled, it risks plunging our country into a turmoil".

Already there is talk within some of the union federation's affiliates of boycotting the municipal elections or refusing to campaign for the ANC.

The ANC, not wanting to lose this election machinery, is likely to use the National Prosecuting Authority (NPA) as a scapegoat.

ANC secretary-general Kgalema Motlanthe has in the past accused former NPA boss Bulelani Ngcuka of conducting "Hollywood-style" arrests.

This is the only bargaining chip the ANC would use to entice Cosatu from making further threats before the elections, and soften Cosatu's demands for charges against Zuma to be withdrawn.

Ntshalintshali has inferred there would be agreement that "Zuma's rights were infringed and prejudiced, and also on the NPA's Hollywood-style raids and the NPA's future".

If, as expected, the ANC commits itself to "deal with the NPA", Cosatu will try to convince the federation's central executive committee that their suspicion of a political plot had been addressed.

With acknowledgements to Jeremy Michaels, Moshoeshoe Monare,Tania Broughton and The Star.