Bushfires have wiped out about half the koalas living on a coastal reserve in New South Wales, experts estimated on Friday, as a record number of intense fires rage around the Australian state.

A fierce early start to the bushfire season brought a blaze at the Lake Innes Nature Reserve that destroyed two-thirds of the koalas' habitat last month, leaving the rest under threat from one of 15 major blazes in the southeastern state.

About 350 koalas living on the reserve in the north coast town of Macquarie have died in the bushfires, the group Koala Conservation Australia estimates.

That compares with a total population of 500 to 600 in the reserve, said the group's president, Sue Ashton.

Animal carers at the Port Macquarie Koala Hospital nearby have been nursing rescued koalas, bandaging their wounds and feeding them eucalyptus leaves and formula.

Amazon rainforest swept by fires: In pictures Show all 25 1 /25 Amazon rainforest swept by fires: In pictures Amazon rainforest swept by fires: In pictures Fire rages in the Amazon rainforest in the Brazilian state of Rondonina on August 23 Reuters Amazon rainforest swept by fires: In pictures Smoke billlows from burning tracts of the Amazon rainforest in the Brazilian state of Para on August 23 AFP/Getty Amazon rainforest swept by fires: In pictures Fire rages in the Amazon rainforest in the Brazilian state of Rondonina on August 23 EPA Amazon rainforest swept by fires: In pictures Land in the Amazon rainforest left scorched in the fires in the Brazilian state of Rondonina on August 23 AFP/Getty Amazon rainforest swept by fires: In pictures Smoke billows during a fire in an area of the Amazon rainforest in the state of Rondonia, Brazil on August 23 AFP Amazon rainforest swept by fires: In pictures Fire tears through a farm in the Brazilian state of Mato Grosso AP Amazon rainforest swept by fires: In pictures An area of the Amazon rainforest left scorched in the fires in the Brazilian state of Amazonas on August 24 AFP/Getty Amazon rainforest swept by fires: In pictures Satellite images show a series of fires in the southwest Brazilian state of Rondonia on August 15 AP Amazon rainforest swept by fires: In pictures Smoke billows during a fire in an area of the Amazon rainforest in the state of Rondonia, Brazil Reuters Amazon rainforest swept by fires: In pictures A satellite image released by NASA shows the active fires that have been detected in the Amazon region EPA Amazon rainforest swept by fires: In pictures Smoke billows during a fire in an area of the Amazon rainforest in the state of Amazonas, Brazil Reuters Amazon rainforest swept by fires: In pictures Smoke billows during a fire in an area of the Amazon rainforest in the state of Rondonia, Brazil Reuters Amazon rainforest swept by fires: In pictures Smoke billows during a fire in an area of the Amazon rainforest in the state of Rondonia, Brazil Reuters Amazon rainforest swept by fires: In pictures Smoke billows during a fire in an area of the Amazon rainforest in the state of Amazonas, Brazil Reuters Amazon rainforest swept by fires: In pictures Indigenous people from the Mura tribe wallk in a deforested area inside the Amazon rainforest in the Brazilian state of Amazonas on August 20 Reuters Amazon rainforest swept by fires: In pictures Fire tears through a farm in the Brazilian state of Mato Grosso AP Amazon rainforest swept by fires: In pictures Smoke billows from a stretch of fire in the Amazon rainforest in the Brazilian state of Rondonia on 23 August AFP/Getty Amazon rainforest swept by fires: In pictures Smoke billows during a fire in an area of the Amazon rainforest in the state of Amazonas, Brazil Reuters Amazon rainforest swept by fires: In pictures Indigenous people from the Mura tribe wallk in a deforested area inside the Amazon rainforest in the Brazilian state of Amazonas on August 20 Reuters Amazon rainforest swept by fires: In pictures Smoke billows from a stretch of fire in the Amazon rainforest in the Brazilian state of Rondonia on 23 August AFP/Getty Amazon rainforest swept by fires: In pictures A view of logs felled illegally in the Amazon rainforest are seen in sawmills in the Brazilian state of Amazonas on August 22 Reuters Amazon rainforest swept by fires: In pictures A scorched patch of land in the state of Mato Grosso in Brazil on 20 August EPA Amazon rainforest swept by fires: In pictures Several fires are seen burning in the Amazon rainforest in this satellite image taken by NASA on 11 August AFP/Getty Amazon rainforest swept by fires: In pictures Smoke billows from a stretch of fire in the Amazon rainforest in the Brazilian state of Rondonia on 23 August AFP/Getty Amazon rainforest swept by fires: In pictures The sunsets behind clouds and smoke from fires in the Amazon rainforest in the Brazilian state of Rondonia on 18 August EPA

"We look for signals of pain – teeth grinding, distress – and we just take it on a day-by-day basis," said Amanda Gordon, who leads the team of carers, adding that some of the koalas health problems can be hard to spot.

"Sometimes koalas seem to be doing really, really well. Their paws might be healing up but if something's going on that we can't see there's not really much we can do," added Ms Gordon, who has worked at the hospital for 15 years.

The carers estimate at least 10 days will be needed to assess the full damage to the koala population.

(AFP (AFP)

Population estimates for koalas, native to Australia, vary widely, from as few as 50,000 to little more than 100,000.

They dwell mostly in eucalypt forests in eastern states and on the coastal fringes, usually living up to 20 years, carrying their young in a pouch and sleeping for up to 18 hours a day.

Warmer weather brought by climate change threatens to worsen conditions for koalas, as deforestation has narrowed habitable areas, said James Tremain of the Nature Conservation Council of New South Wales.

Australia: Koala rescued from raging bushfire

"Devastating bushfires are going to knock out some of these key population centres, but so also will increasing temperatures," he said, by affecting the nutrition value of the leaves that are the animals' sole food source.

"Koalas are definitely in trouble in New South Wales, but if the declines continue at the same rate as the last 20 to 30 years, koalas could be extinct in the wild by mid-century," Mr Tremain added.