"They listened to our arguments and have agreed to postpone the cull, but we don't know for how long," said Rudi van Aarde on Wednesday. "We want at least three years for more research."

Van Aarde, on a brief lecture tour of Britain, is professor of conservation ecology at the University of Pretoria and a member of a panel of scientists set up to advise the government on the proposed cull.

The SANParks proposal could have meant removing thousands of elephants from the 12,500 in the sprawling park, where the optimal number had been set at 7,000 for about 30 years.

In the years before the ban, more than 14,000 elephants had been culled to keep numbers around 7,000.

A spokesman for the South African Environment Ministry denied any specific figure had been considered, and said consultations on a range of options were still under way.

The elephants have been accused of damaging large sections of the park because they bring down trees and crowd around watering holes placed for the convenience of tourists.

"Remove the artificial watering holes and the elephants will resume their natural behaviour of seasonal migration, giving places they have left a chance to recover," van Aarde told a briefing organised by the International Fund for Animal Welfare.

He also discounted a problem with the people who live around the park's borders, noting that population density was very low to the north of the park.

But in place of parks like Kruger - which stretches along the border with Mozambique - van Aarde proposed creating a vast multinational conservation region.

The proposed area runs north of a line across South Africa from the south of Kruger to southern Namibia up to a line crossing from southern Angola to northern Mozambique and taking in Botswana, Zambia, Zimbabwe and Malawi on the way.

This area already contains 116 million people and 270,000 elephants, he said.

The seven megaparks within the conservation area would house "metapopulations" - a concept devised in Finland in the 1960s in a study of butterflies and meaning isolated populations of animals which occasionally intermingle.

Not only would this relieve the environmental pressure on restricted game parks like Kruger, but it would also promote biodiversity and could help animal populations to cope better with effects of global warming such as droughts.