The new aircraft, which can fly as far as 350 kilometres from their bases at Bunbury and Jandakot, will begin service in late 2023.

Capable of being airborne in less than 15 minutes, the rescue service's helicopters have flown almost 9000 missions since 2003, providing vital search and rescue capabilities.

"In the direst times of need, the Emergency Rescue Helicopter Service has saved thousands of Western Australian lives and supported some of the most complex emergency operations across our state," Emergency Services Minister Stephen Dawson said.

Mr Dawson said the mission equipment fit-out on the new aircraft would also be completed in Perth, boosting local jobs in the aerospace sector.

Fire and Emergency Services Commissioner Darren Klemm said the helicopter service was adaptable to respond to a range of emergencies, including major traffic crashes, searches, and cliff and sea rescues, often in areas that were inaccessible by other means.

"This significant upgrade will provide even more capability to support cyclones and flooding in remote areas and respond to bushfires where medical evacuations are required," he said.

"The fit-out includes improved night vision imaging systems to respond to incidents at all hours, search and rescue radars to access difficult terrain and complete complex rescues, and the most advanced critical care aeromedical equipment of any rescue helicopter in Australia."

Australian Associated Press