Most of the elephants dying in the Pandamasue Forest between the vast Hwange National Park and Victoria Falls were young or weak, National Parks and Wildlife Management Authority spokesman Tinashe Farawo said on Wednesday.

With food scarce, younger elephants that can't reach higher tree branches "end up eating everything and some of the vegetation that they eat might be poisonous", Farawo said.

He said the problem could persist through the dry season.

Zimbabwe has been facing successive climate-induced droughts, leaving animals with less water and vegetation.

Apart from possible bacterial infection, some of the animals could be dying due to the stress of walking long distances for food and water.

Farawo said overpopulation had become "the biggest threat" to the survival of wildlife in the southern African country's parks. The "animals are becoming a threat to themselves", he said.

The dead young elephants were found with their tusks still on their bodies, ruling out poaching.

In recent years poachers in Zimbabwe have poisoned dozens of elephants with cyanide and taken their ivory tusks to sell.

Investigations will also try to establish if there is a link between the deaths and those reported in neighbouring Botswana.

Scientists are investigating the deaths last month of more than 275 elephants in Botswana's Okavango Delta area. Poaching, poisoning and anthrax have also been ruled out in those deaths.

Botswana has the world's largest elephant population, estimated at 156,000 and Zimbabwe the second largest, estimated at 85,000.

Last year about 200 elephants in Zimbabwe died of starvation as a result of the country's drought.

Australian Associated Press