More than 80 elephants and other animals have died of cyanide poisoning by poachers in Zimbabwe's largest game park, wildlife authorities said Tuesday.

The announcement came after a group of government experts visited Hwange National Park on Saturday to investigate reports of cyanide poisoning.

"When we left Hwange National Park on Sunday, the total number of elephants that had died from cyanide poisoning was 81," said Jerry Gotora, a director of the Zimbabwe parks department.

"Several other animals have also died, but we don't have the total number yet."

More than 25,000 elephants were poached last year, according to the Convention on International Trade in Endangered Species (CITES).

The animals' tusks are highly sought after for Asia's ivory trade.

Nine people have been arrested on suspicion of poisoning watering holes in the game park to kill the elephants for their tusks.

However, Gotora said the poison had been "put at places where elephants graze, not in water as was being reported".

Two years ago nine elephants, five lions and two buffalo died from cyanide poisoning in Hwange National Park.

Just 50 rangers patrol the 14,650-square kilometre (5,660-square mile) park, and wildlife authorities say 10 times that number are needed.

There are more than 120,000 elephants living in Zimbabwe's national parks.