Joondalup Health Campus, in Perth's northern suburbs, will use the money for 90 new inpatient beds for future demand, 30 new beds for mental health inpatients, six critical care beds and two operating theatres.

Drug- and alcohol-affected patients presenting to the emergency department will be treated in a separate, specialist urgent care clinic area, while an extra 12 treatment bays will be added to the same department thanks to the cash splash.

There are also plans for more than 360 new car parking bays.

Health Minister Roger Cook says his party's election commitment has finally been met.

"Another $96 million in the expansion of Joondalup Hospital to meet the needs of the people in the northern suburbs," he told reporters.

It comes after the hospital received $158 million from the federal government.

Works on the hospital are expected to start early to mid next year.

Australian Associated Press