TasNetworks says the number of wedge-tailed eagles dying after coming into contact with electricity network infrastructure has increased by over 140 per cent in a year.

Twenty-nine wedge-tailed eagles were killed in 2017-18, up from 12 killed the previous year.

TasNetwork has spent about $600,000 installing infrastructure to reduce the impact on the threatened birds.

Tasmanian wedge-tailed eagles are an endangered species, with an adult population of about 350 breeding pairs.

BirdLife Tasmania convenor Eric Woehler said it was a “terrible loss”.

“To lose 29 birds in one year is a significant number of birds, and it's a significant hit on the population in Tasmania,” he said.

“They're a long-lived bird, they can live for 30 or more years. To lose this many birds is going to take a long time — if ever — for the population to recover.

“The population is decreasing at such a rate that it meets the international criteria for listing as an endangered species.

“If we don't stop the threats that have been identified … the species will go extinct.”

TasNetworks chief executive Lance Balcombe said the organisation would continue working with scientists to develop an eagle risk strike model and install more mitigation devices.

“We got the message out to the community — farmers, in particular — that we want to hear about eagle mortalities because with that data, although it's a bad outcome where a bird is killed, the good thing is we can do something with that data,” he said.

“We can go and mitigate that part of the network, and the more data we have, that will go and help the science that we're trying to develop.”