A spokesman for the ruling African National Congress said Tsvangirai had met Zuma in Johannesburg but gave no details.

Tsvangirai, who says he defeated Mugabe in a presidential election on March 29, wrote in a newspaper article earlier that Zimbabwe was on a "razor's edge" because of the veteran leader's attempts to prolong his rule. South African President Thabo Mbeki, who says there is no need for outside intervention in Zimbabwe, was dislodged as leader of the ANC by Zuma last December.

Zuma said in an interview with the Wall Street Journal carried out before the Zimbabwe election that South Africa should continue Mbeki's policy of engaging with Mugabe to try to find a solution to his neighbour's crisis.

But Zuma, frontrunner to succeed Mbeki as president in 2009, said political leaders should not stay in power for more than a decade.

Earlier on Monday Zimbabwe's High Court again postponed a decision on an opposition bid to force release of the result of the presidential election, which Mugabe wants to delay.

The High Court rejected a Zimbabwe Electoral Commission (ZEC) argument that it had no jurisdiction over the release of results but postponed until Tuesday a ruling on whether it should consider the case urgently.

Tsvangirai's Movement for Democratic Change has been trying since Saturday to accelerate release of the results.

Tsvangirai accuses Mugabe of planning violence to overturn results of both presidential and parliamentary votes. The ruling ZANU-PF party wants a delay pending a recount, as part of its strategy to extend Mugabe's uninterrupted rule since independence from Britain.

The opposition and Western powers blame Mugabe for reducing his once prosperous country to misery by economic mismanagement.

Zimbabwe has the world's worst rate of hyper-inflation, making its currency virtually worthless and turning millions of people into economic refugees.

The opposition says Mugabe is trying to buy time to organise a fight-back after his first electoral defeat, when ZANU-PF lost a parallel parliamentary election.

Tsvangirai wrote in Britain's Guardian newspaper on Monday: "Major powers here, such as South Africa, the U.S. and Britain, must act to remove the white-knuckle grip of Mugabe's suicidal reign and oblige him and his minions to retire."

President Mbeki, who failed last year to mediate an end to the Zimbabwe crisis, said at the weekend the post-election situation there was "manageable".

ZANU-PF and independent monitors' projections show Tsvangirai has won the presidential election but will be forced into a runoff vote after failing to win an absolute majority.

JOURNALIST HURT

Two Western journalists arrested last Thursday were granted bail on Monday but a lawyer for New York Times correspondent Barry Bearak said he had been taken to hospital after suffering serious injuries in jail.

"He fell in the cells and sustained serious injuries, so he needs medical attention," lawyer Harrison Nkomo said, adding that Bearak, a Pulitzer Prize winner, had hurt his back. Nkomo made no suggestion of foul play.

Bearak and a British reporter were arrested at their hotel and charged with covering the election without accreditation.

ZANU-PF's strategy to stay in power includes legal challenges to some of the parliamentary results and the mobilisation of pro-government militias before any runoff.

The re-emergence of liberation war veterans, often used as political shock troops by Mugabe, has increased concern that he plans a violent response to his election setback.

The veterans led a wave of violent occupations of white farms as part of a government land redistribution programme.

MDC Secretary-General Tendai Biti said ZANU-PF had "unleashed war and terror on farmers perceived to be sympathetic to the MDC," while attacking other opposition supporters.

Electoral rules say a runoff must be held three weeks after the release of results, meaning the longer the delay the more time Mugabe has to regroup.