A north Queensland vet says he could be forced to euthanise injured and orphaned cassowaries after the closure of the only rehabilitation centre for the endangered species.

The Department of Heritage Protection has announced the Garners Beach Cassowary Rehabilitation Centre in Mission Beach would close once three birds now in care were ready to be released.

Australia's only cassowary rehabilitation centre is to close.

Dr Graham Lauridsen, who is involved in the program, says he'll have nowhere to take birds that have been injured or orphaned by cars.

He said one treated cassowary, taken in after being hit by a car, had recently been spotted mating in the wild after its release.