The process – a precursor to proposed multiparty elections – will take place amid warnings that Zimbabwe’s fragile political accord might unravel within weeks if President Jacob Zuma does not intervene.
The agreement underpinning the unity government has teetered in recent months, with the Movement for Democratic Change repeatedly accusing Zanu-PF of failing to deal with serious obstacles to the implementation of true multiparty rule.
The drafting of a new constitution is likely to add to the tensions between the rival political parties.
At the weekend, MPs from all parties were summoned by Zanu-PF, through state radio broadcasts, to take part in a joint preparatory "caucus". Ordinarily, a meeting of this nature would be called by the Speaker of the House of Assembly.
It was not known late yesterday if MPs from the MDC would attend.
The party’s leader, Prime Minister Morgan Tsvangirai, has already thrown down the gauntlet, saying that, if all the outstanding issues bedevilling the unity government were not resolved by the middle of this month, he would ask for further arbitration by the Southern African Development Community.
Since the formation of the coalition government, in February, land invasions and state harassment of MDC supporters have continued.
President Robert Mugabe has unilaterally appointed key state officials and has refused to swear in Tsvangirai’s nomination for the post of deputy agriculture minister, Roy Bennett, who was arrested on what his party claims are trumped-up charges.
The crucial positions of central bank governor and attorney-general – both occupied by Mugabe loyalists – are another major source of tension.
The Sunday Times yesterday quoted MDC founder member Eddie Cross as saying that Zimbabwe’s crisis was likely to worsen sharply in coming weeks and that only decisive action by the South African government could save the unity agreement.
Zanu-PF has said it will make no "further concessions" to the MDC.
Tensions in the unity government are expected to play out in parliament, where Tsvangirai’s MDC has a slender majority.
The party has warned that more reforms are necessary to keep the unity government afloat. Commissions to oversee media, elections and rights reform have been agreed to but are yet to take office.
A Zimabawean MP warned this week that the country’s tenuous political accord would unravel within weeks if President Jacob Zuma did not intervene decisively to force its implementation.
Eddie Cross, a founder member of Morgan Tsvangirai’s Movement for Democratic Change and its policy co-ordinator, told the Sunday Times he expected a showdown within days.
"I think as soon as the government is back in the new year – on Monday – the crisis will escalate sharply unless Mr Zuma steps up to the plate and does what (former South African prime minister John) Vorster did to (Rhodesian leader) Ian Smith in 1976 and what Mr (Thabo) Mbeki did to Mr (Robert) Mugabe in 2007.
"Mr Zuma has to say to Mr Mugabe behind closed doors, as Vorster said to Smith: ‘It’s the end of the road,’" Cross said in an interview in Cape Town.
He said South Africa had intervened decisively twice to help Zimbabwe towards a political solution, but had failed both times to follow up by holding the parties to account for their implementation of agreements.
The first was when then-president Mbeki forced Mugabe to reverse the postponement of an election and go to the polls in 2008 with effective rules for a free and fair election.
Mbeki allowed Mugabe to force a runoff in the presidential election, however, and to rig the results of the second poll.
As a result of South Africa’s second intervention, Tsvangirai’s MDC and Mugabe’s Zanu-PF share power under a global political agreement facilitated by South Africa almost a year ago – but implementation of the 34 requirements of the accord has stalled with no action on half of them.
Cross said Zuma had shown his skill in Southern African Development Community meetings on Zimbabwe: "He’s a very cunning politician."
Cross said the MDC had made all the major concessions on the agreement and could not give further ground.
"We are not prepared to make further concessions with regard to the fundamental principles enunciated in the agreement – we’re not prepared to do so," he said.
He said Zanu-PF had stalled the negotiation and implementation of a new constitution and had blocked the transfer of the security forces to civilian control. Human rights, media freedom and the security of property rights had all moved backwards since the accord was signed.
"We are back where we were in April 2008. South Africa is confronted with a situation where Zanu is unprepared to accept the outcome of a political process which has been initiated and managed by the South African government. The question now is: What do we do?"
The SADC recently put Zuma in charge of efforts to resolve the impasse in Zimbabwe.
He immediately appointed former cabinet ministers Mac Maharaj and Charles Nqakula and his foreign policy adviser, Lindiwe Zulu, to drive the process.
Mugabe skipped his usual overseas Christmas holiday and Cross said the parties to the agreement, which includes a breakaway MDC faction led by Arthur Mutambara, had held almost continuous talks throughout the holiday season with no sign of a breakthrough.
Mugabe said at a rare joint news conference with Tsvangirai 10 days ago that the parties to last year’s agreement were committed to the implementation of the accord, but Cross said Zuma had repeatedly postponed a visit to oversee the signing of a new implementation agreement, which suggested progress was still stalled.
"In effect, the political, social and economic crisis is re-emerging in Zimbabwe. We will slide into a condition very quickly in the new year, where the new government will become totally dysfunctional.
"The crisis will come because, I think, the MDC will simply say it can’t be business as usual.
"I think the crisis will be triggered by the MDC, but the real issue is whether South Africa will exercise its responsibility and authority. The indications at the present time are: No."