IT'S deadline day for ANC president Jacob Zuma, with marathon discussions over the dropping of corruption charges against him expected to be concluded today, and the cut-off looming for his application to the Constitutional Court.

Zuma's legal team, which was due to have filed documents relating to his attempt to have his criminal prosecution declared invalid on Friday, asked for an extension, according to a court official.

National Prosecuting Authority (NPA) spokesman Tlali Tlali confirmed this morning that discussions about a final decision on whether the charges against Zuma would be dropped would continue today. But he would not go so far as to confirm whether a decision would come in time for the Constitutional Court deadline.

Yesterday, acting prosecutions boss Mokotedi Mpshe and his deputy, Willie Hofmeyr, met with their team for more than 12 hours to deliberate on representations submitted by Zuma's legal team.

It "was not an easy meeting", NPA communications manager Bulelwa Makeke said.

Zuma's submissions allegedly include embarrassing taped recordings of conversations between former NPA heads and former president Thabo Mbeki, which allegedly indicate there was political collusion behind Zuma's prosecution.

While the nation anxiously awaits the NPA decision, Tlali said that "outstanding issues could be discussed exhaustively" when the meeting reconvened today.

As soon as a decision is made, Mpshe is likely to inform Justice Minister Enver Surty. The NPA and Zuma's legal team will then approach the Pietermaritzburg High Court to consult with Judge President Vuka Tshabalala.

Yesterday Surty broke his silence on Zuma's representations, urging the NPA and Mpshe - who must make the final call - to have the courage to make a bold decision.

Should no decision be reached by this afternoon, Zuma's lawyers would have to file their papers today for their Constitutional Court bid.

Zuma's lawyer could not be reached for comment to ascertain whether they still intended to file their arguments.

Meanwhile, political commentators and opposition parties have urged the NPA to disclose full reasons for the expected decision to stay the charges.

DA leader Helen Zille maintained that if Zuma was indeed innocent, he had to clear his name in a court of law. "If we allow Zuma to escape his day in court as a result of a back-room deal with the NPA, we will be no closer to knowing whether he is guilty or innocent.

"There will be a cloud hanging over his head and the entire government. Escaping prosecution is not the same thing as acquittal. If he never appears in court he cannot be presumed innocent."

Constitutional law professor Pierre de Vos warned that if the NPA dropped charges "despite the fact that all available evidence" suggested Zuma had a serious case to answer, the decision could be illegal.

"It would constitute the most flagrant abuse of power and the law, and would thus undermine respect for the Rule of Law," De Vos writes on his blog, Constitutionally Speaking. "That is why the NPA has a duty to explain a decision to drop charges against Jacob Zuma in full."

De Vos said it was necessary for the NPA to present the public with a "cogent and logical explanation" of why the law required them to drop the charges.

"Only then will we be able to say whether this was a flagrant, illegal act by the NPA, or something done in terms of the legal rules."

But deputy NDPP and head of the NPA's Asset Forfeiture Unit, Willie Hofmeyr, said last week that the reasons would "probably" be made public.

However, well-placed sources have indicated that some of the reasons, including the content of the tape recordings, may be withheld in the interest of "national security".

University of Johannesburg deputy vice chancellor, Adam Habib, said transparency of the process was imperative to ensure that confidence in South Africa's institutions was repaired in the aftermath of the bruising battle between Zuma and the NPA.