President Thabo Mbeki will go into battle against supporters of the fired deputy president Jacob Zuma this week when he tries to persuade the ANC’s National Executive Committee to launch a commission of inquiry into the affair.

The top-level NEC meeting — which starts on Friday and ends on Sunday — will be the first since the party’s National General Council, where delegates openly revolted against Mbeki. This is one of the most anticipated meetings in recent times.

Mbeki last week proposed that a commission be established to settle once and for all whether he was leading a conspiracy to sideline Zuma, as has been claimed by several high-profile figures in ANC circles.

Cosatu and the South African Communist Party have rejected the proposal.

Mbeki, who believes he is being fingered as the lead conspirator, will table his commission proposal to the ANC’s powerful NEC this weekend.

If he succeeds, it will deal the Zuma camp a severe blow. But should he fail to win the NEC’s support, he will find himself isolated within the party and the door will be further opened to Zuma taking over as president of the ANC in 2007.

ANC spokesman Smuts Ngonyama, who is also a member of the NEC, told the Sunday Times on Friday that the Zuma affair had reached “critical point” and a solution needed to be found “urgently”.

At the crunch meeting, the Zuma camp is likely to be represented by several ANC provincial chairmen and secretaries. Zuma has strong support in at least seven of the provinces.

His supporters will also include ANC Youth League president Fikile Mbalula and SACP general secretary Blade Nzimande.

Mbeki is likely to be backed by most members of his Cabinet. He also has the support of the ANC Women’s League.

The meeting is critical for Mbeki, who has recently suffered two political blows.

Just last week, a meeting of the ANC and its Cosatu and SACP allies issued a statement backing Zuma.

Before that, the ANC’s National General Council stunned Mbeki by challenging his dismissal of Zuma and reinstating him to his ANC post. The council did not have the authority to restore Zuma as deputy president of the country.

It will also be the first time both Mbeki and Zuma face the NEC to discuss the volatile issue, which has split the ANC down the middle.

Mbeki fired Zuma after a Durban High Court judge found proof of a “generally corrupt relationship” between Zuma and Durban businessman Schabir Shaik.

Mbeki first proposed a commission of inquiry into the alleged plot against Zuma in a letter read by ANC secretary-general Kgalema Motlanthe at the meeting of the ANC and its allies last week.

He subsequently made his letter public, sparking an angry response from Cosatu and the SACP, who accused him of acting in bad faith.

“This meeting is long overdue,” said one veteran NEC member. “There’s been so much smoke that people have lost sight of whether there is a fire and, if so, where it is.”

Some members of the NEC canvassed by the Sunday Times criticised Mbeki’s failure to consult more fully about his management of the Zuma affair, but others faulted Zuma for putting his own ambitions ahead of the best interests of the ANC and the country.

On Friday, the unrepentant ANC Youth League backed Cosatu and the SACP in rejecting Mbeki’s proposal of a commission of inquiry.

Mbalula said: “Problems within the party cannot be subjected to legalistic and technical methods.”

He told the Sunday Times that Mbeki’s proposed commission was “not the correct method to manage the Zuma issue. Commissions are going to suffocate the nature of our movement [the ANC]”.

Mbalula praised “those who are alleging a political conspiracy”, describing them as “brave”.

Despite opposition from ANC allies, Mbeki appears determined to press ahead with the commission.

Ngonyama said he believed the commission would bring an end to statements by the alliance partners about their unhappiness over the handling of the Zuma affair.

“The statements that have been coming from Cosatu and the SACP have been loaded and can be interpreted in whatever way,” he said.

Ngonyama said Mbeki had been on leave last week when he wrote the letter “straight to Motlanthe”, proposing a commission “after reading newspaper reports and watching statements on television by a number of the leaders of the alliance about the political conspiracy”.

A senior NEC member said he believed the commission would achieve its objectives “if it has buy-in, particularly of people insinuating allegations of conspiracy, otherwise it becomes a white elephant”.

Two of the nine provinces have come out in support of Mbeki’s proposal. Limpopo ANC secretary Cassel Mathale said: “We want to get to the bottom of the allegations of a conspiracy ... Whatever form that will take, we will support it.”

The ANC provincial secretary in the North West, Supra Mahumapelo, said: “The commission will make us better understand suggestions that there are efforts within the ANC to discredit our beloved and respectable deputy president, Jacob Zuma.”

Meanwhile, the Free State, Eastern Cape, Gauteng, KwaZulu-Natal and Western Cape claimed they had not discussed the matter. Mpumalanga refused to comment, while the Northern Cape was not available.

With acknowledgements to Brendan Boyle, Xolani Xundu, Moipone Malefane, Ndivhuho Mafela and the Sunday Times.