In a twist worthy of a soap-opera, the country's official opposition has been given a chance to argue before state prosecuting authorities why corruption charges against the leader of the ruling party should go ahead.

Acting national prosecutions chief Mokotedi Mpshe yesterday told DA leader Helen Zille her party would be "most welcome" to set out its case forwhy charges against ANC president Jacob Zuma should not be dropped.

But he asked that the party submit its written representations before Friday - the date Mpshe says he has set "for myself to apply my mind to all the information supplied and still to be supplied" before deciding whether or not to proceed with the prosecution.

That means the country - and Zuma - will have to wait at least another week before getting a final answer on whether the man most likely to be the next president of the country will have to step into the dock, or can walk free.

While Zuma's legal team has consistently refused to divulge what its own representations to the NPA contained, there has been speculation that it included new evidence that has never seen the light of day.

Reports yesterday fuelled that speculation, with The Times reporting that, according to sources familiar with the case, Zuma's legal team is relying on secretly taped recordings of Scorpions investigators allegedly mulling over the case against Zuma with Mpshe's predecessor Bulelani Ngcuka.

Meanwhile, the Mail & Guardian reported yesterday that Zuma's lawyers had given the NPA fresh "evidence" of alleged impropriety on the part of former president Thabo Mbeki in the awarding of arms deal contracts, as well as alleged political interference in Zuma's prosecution.

The reports came in a week that saw outrage ignited on both ends of the political spectrum by leaks suggesting the NPA was poised to end eight years of investigations by dropping its case against Zuma.

The ANC's Lindiwe Sisulu said it was vitally important for the ruling party - and the country's reputation - that people would be able to buy into the final decision regarding Zuma - be it his conviction, or the withdrawal of charges.

The DA's Zille threatened that her party would consider a private prosecution against Zuma if charges were dropped - as did Patricia de Lille, leader of the Independent Democrats.

After advice from lawyers, Zille decided to ask Mpshe for the party to be allowed to make representations.

Constitutional law expert Pierre de Vos said a situation where the official opposition gets to argue why the ruling party's boss should be prosecuted was unprecedented.

De Vos said it would be very difficult for anyone to introduce a private prosecution.

The law requires that anyone who wants to do so would have to show a substantial interest in the issue of the trial, arising out of an injury they suffered personally as a consequence of the offence.