"There are very clear signs … people are beginning to die of starvation," said government spokesperson Themba Maseko.
South Africa and the the Southern African Development Community (Sadc) could not just stand by and do nothing, he added.
President Kgalema Motlanthe will meet with ministers to look at how South Africa could work with neighbouring countries, donors and aid agencies to address "the urgent need for food and other humanitarian needs," Maseko said.
Zimbabwe is appealing for international aid after declaring a cholera epidemic a national emergency, the country’s state-run Herald newspaper said Thursday. The outbreak has so far claimed 565 lives, according to UN figures.
Although South Africa was closely monitoring the situation, Maseko said the government would stand by a decision to withhold nearly $30-million earmarked for agricultural aid until a unity government was formed.
South Africa in October approved R300-million ($30-million / €23-million) in agricultural aid to Zimbabwe, subject to conditions, to help short-term food needs.
Maseko said South Africa would pressure Zimbabwe’s political leaders to sign a crucial constitutional amendment within the next few days.
Zimbabwe President Robert Mugabe’s Zanu-PF party and the opposition Movement for Democratic Change (MDC) have agreed a draft, which sets out the powers of the new prime minister, but the amendment has yet to be finalised.
"We will continue to put pressure on the principals to sign the agreement as soon as possible," said Maseko.
A deal signed on 15 September that provided for the formation of a unity government has stalled as parties failed to reach a consensus on the allocation of key cabinet posts.
Opposition leader and prime minister designate Morgan Tsvangirai has called for former president Thabo Mbeki to step down as mediator.
But Maseko said the Sadc and the South African government still had full confidence in him.
"There is no basis for us to begin to doubt the facilitation process of Thabo Mbeki," he said. – AFP