Female koalas at Cape Otway on Victoria's Great Ocean Road will be given a contraceptive implant as wildlife officers report soaring numbers are causing starvation among the population.

Officers will catch, sedate and assess the health of about 100 koalas this week, with any koalas deemed too unhealthy to be released to be put down.

Wildlife officers said a population spike had seen many koalas die of starvation, and last year about 700 koalas were put down.

Dr Jack Pascoe from the Conservation Ecology Centre said the koalas were at great risk.

"An imbalance in the ecosystem led to a catastrophe - koalas were, through no fault of their own - eating away their habitat," Dr Pascoe said.

"Trees that should have been regenerating and growing leaves simply could not recover. Seedlings did not emerge from the ground. Koalas starved."

Mandy Watson from the Department of Environment, Land, Water and Planning said there were still too many koalas at Cape Otway.

"Sustainable density is thought to be about one per hectare, and what we're observing is about three to four as a minimum and up to about 20," Ms Watson said.

She said the spike in the population had led to the destruction of hundreds of manna gum trees.

"It's still looking pretty poor, there was some leaf recovery post the crash, but overall things are looking pretty poor and koala numbers are still high," she said.

She said the health assessments were the first step towards a broader management plan for the koalas in the area.

"We need to gather information from this health assessment, and then we'll look at doing some habitat mapping and some species distribution modelling, and then we'll develop a management plan," she said.

Ms Watson said it was possible the koalas could be relocated to another area, if somewhere appropriate was found.

'Whole cape smelled like dead koalas'

Frank Fotinas, who has managed the Bimbi Park caravan park at Cape Otway for 10 years, said the overpopulation of koalas had been hard to watch.

"You were seeing dead koalas at the base of the trees, stripped trees, whole forests and just the koalas sitting on the bottom of the trees, dying," he said.

One of the Cape Otway koalas receiving a health check. ( ABC: Margaret Paul )

"The whole cape smelled like dead koalas."

Mr Fotinas said a management plan should include planting more trees.

He said he did not want to see the koalas culled but something had to be done to restrict their numbers.

"I want to protect the koalas too, I mean the koalas are great for business, they're great for tourism in Australia and they are a beautiful little animal, but they're breeding in plague proportions," he said.

"They're killing off their own habitat, so it's going to come to a point where we're going to have no manna gums and no koalas."