A population explosion in the Otway Ranges has forced vets to carry out an extensive program of health checks because of an increasing number of koalas starving to death.

As of Wednesday, 76 koalas had been assessed, of which 63 were released and 13 unhealthy animals euthanised.

The program is focused on koalas in remnant manna gum woodland and is the first action to come out of recommendations developed by an expert panel.

In late 2013 and 2014, Department of Environment Land Water and Planning initiated a welfare intervention program at Cape Otway to respond to the issue of starving koalas after the local population expanded to unsustainable levels, devastating their habitat.

According to the department there had been a slight improvement in manna gum foliage in some areas, but koala density was still high at Cape Otway and proactive management was needed to protect koala welfare.

Department spokeswoman Mandy Watson said koala welfare and habitat continued to be the top priority.

“We are focusing our attention on private land in Cape Otway where koalas are most affected by over-browsing.

“The health assessment is expected to run for a week and includes catching a representative sample of koalas, examining them, ear-tagging and implanting fertility control in the females prior to release.

“Any unhealthy koalas, which are deemed too sick to survive release will be humanely euthanised to prevent further suffering.” Conservation Ecology Centre chief executive Lizzie Corke told The Standard the issue of an expanding koala population was also happening around Framlingham, Tower Hill and Mt Eccles and through to South Australia and Kangaroo Island.

Conservation and research manager at the centre, Jack Pascoe, said an imbalance in the ecosystem led to a catastrophe where koalas were eating away their own habitat.

“Trees that should have been regenerating and growing leaves simply could not recover,” Mr Pascoe said.

He said examinations the vets carry out were vital for understanding the koalas’ current health levels across habitat of different qualities and informing future actions to help keep marsupials healthy.

The Conservation Ecology Centre has been protecting important seed trees to gather seed and grow seedlings, and is spearheading a program to restore habitat across Cape Otway. So far nearly 100,000 young trees have been planted by volunteers.