South African ruling party leader Jacob Zuma called on Tuesday for African action to resolve Zimbabwe's crisis, amid signs of increasing regional impatience with President Robert Mugabe.

Maritime southern African states refused to allow a Chinese ship carrying arms to landlocked Zimbabwe to unload, in unprecedented action towards Mugabe by long-passive neighbours, including traditional allies.

The action indicated a tougher response by the region, which has been criticised, particularly by the United States, for not doing more to end a three-week delay in issuing results from a presidential election on March 29.

Opposition leader Morgan Tsvangirai says he won the vote and Mugabe's 28-year rule is over.

In his toughest comments yet, African National Congress leader Zuma said in a Reuters interview in Berlin:

"It's not acceptable. It's not helping the Zimbabwean people who have gone out to ... elect the kind of party and presidential candidate they want, exercising their constitutional right."

Zuma, who has distanced himself from the "quiet diplomacy" of South African President Thabo Mbeki over Zimbabwe, added: "I imagine that the leaders in Africa should really move in to unlock this logjam.

"Concretely this means African countries should identify some people to go in there, probably talk to both parties, call them and ask them what the problem is, as well as the electoral commission".

Zuma toppled Mbeki as ANC leader last December and has gradually increased his power at the expense of the president. Analysts say he has seized on Zimbabwe as a golden opportunity to improve his international image and influence.

His comments were one factor helping to lift the rand currency to a seven-week high against the dollar. Traders welcomed Zuma's readiness to take a lead on Zimbabwe after concern the crisis would hit Africa's biggest economy.

Zimbabwe has postponed an annual summit of Africa's largest trading bloc which it was scheduled to host next month because of the election impasse, state television reported.

The 19-nation Common Market for Eastern and Southern Africa (COMESA), chaired by Zimbabwe, was scheduled to hold a two-week summit from May 1-15.

HONOURABLE EXIT

Tsvangirai called for African leaders to acknowledge that he won the vote, saying Mugabe would be allowed an honourable exit.

Africa's reputation would suffer "serious disrepute" if Mugabe stayed in power, Tsvangirai said in Accra.

The United States said it was pleased by China's statement that it may have to bring its vessel carrying a shipment of weapons for Zimbabwe home after being unable to unload in southern African ports.

Washington had discouraged Beijing from sending arms to Zimbabwe and asked neighbouring states not to let it dock.

Human Rights Watch urged the Chinese government to immediately recall the weapons.

"China prides itself on being a 'responsible power'," said Sophie Richardson, Asia advocacy director at the group. "This means it has no business shipping arms to an abusive government in the middle of a brutal and violent crackdown."

Zambia, which has been one of the more critical countries in the region over a crisis that has wrecked Zimbabwe's economy, urged neighbouring states to bar the ship from entering their waters, saying the weapons could deepen the election crisis.

Zambia is chair of the regional group SADC (Southern African Development Community).

The Chinese ship was unable to unload in its original destination of Durban on the Indian Ocean coast after trade unions - which are allies of Zuma - refused to handle the cargo, saying the weapons could be used against the opposition.

After it left South Africa, both Mozambique and Angola said it was not welcome.

The MDC deprived Mugabe's ZANU-PF party of its majority in parliament in a parallel vote on March 29 but there has also been a delay to a partial recount of votes from that poll.

The recount could overturn the MDC victory. The opposition and Western governments say it is merely another ploy by Mugabe to steal back the election.