Australia's largest bird of prey, the Tasmanian wedge-tailed eagle, is 11 deaths closer to extinction, the state's power company has confirmed.

Key points: Power company says work being done to mitigate deaths

Power company says work being done to mitigate deaths 300 breeding pairs thought to exist in Tasmania

300 breeding pairs thought to exist in Tasmania 11 birds electrocuted last financial year

The state electricity distributor TasNetworks said the endangered birds were electrocuted flying into powerlines in the last financial year.

There are thought to be only 300 breeding pairs of the birds remaining in Tasmania.

According to Parks and Wildlife, Tasmanian wedge-tailed eagles - which can stand a metre tall and boast a wingspan of up to 2.2 metres - have evolved into their own subspecies after 10,000 years of isolation from their mainland counterparts.

Dr Eric Woehler, of Birdlife Tasmania, said the losses were concerning.

"Any loss of individuals, be it youngsters or adults, poses further risk to the population in Tasmania," he said.

"It basically is putting pressure on the population because it means that those birds have been taken out from unnatural reasons.

"It's taking birds out faster than they can be replaced, so the population is going to continue to go downward."

While Tasmania's population is listed as endangered, elsewhere the conservation status is listed as "secure", with numbers booming in South Australia.

TasNetworks installing bird perches, flight diverters

On its website, TasNetworks states it had spent "almost $1 million over the last 5 years ... mitigation includes the installation of various devices to make conductors more visible to birds and to reduce the risk of electrocution to birds that perch on poles".

An expert says bird-proofing the entire powerline network is unfeasible. ( Supplied: Nick Mooney )

"Our Design Team is encouraged to specify mitigation on higher risk lines and locations: bird perches, insulator covers, conductor covers, bundled cable, flight diverters etc. Currently work is being undertaken to provide more stringent guidelines for designers on requirements to reduce the risk to birdlife."

TasNetworks said it was "voluntarily offsetting our unavoidable impact through partnerships with wildlife sanctuaries.

"We aim to build their capacity to rehabilitate birds of prey and where possible release them back to the wild."

Dr Woehler said TasNetworks would be better off investing in ways to prevent further bird deaths.

"To implement distracters on the entire network of overhead powerlines in Tasmania is beyond practical," Dr Woehler said.

"What we need to look at is where the hot spots are, where the birds are being killed in higher numbers or in greater numbers, or frequently," he said.

The release of the death toll follows a warning the number of eagles being electrocuted by powerlines could be much higher than official statistics indicate.