The average time patients have had to wait at Peel Health Campus' (PHC) emergency department has increased by 61 minutes over the last seven years - the biggest blowout of any hospital in Western Australia.
The Mandurah Mail has compared ED wait times from 2011-12 to 2017-18 across WA's 24 major hospitals, with the increase at PHC the highest of those available on record.
The Mandurah hospital's median wait time in 2011-12 was 1 hour 59 minutes, but this has increased by 61 minutes to 3 hours in 2017-18.
The closest increase to PHC was 45 minutes recorded in Albany, where the wait time has jumped from 1 hour 24 minutes in 2011-12 to 2 hours 9 minutes in 2017-18.
Both Rockingham General Hospital and Bunbury Hospital have increased by roughly 30 minutes in the same time period, while other major facilities, such as Royal Perth Hospital, have seen wait times drop over the last seven years.
A Peel Health Campus spokeswoman said the hospital was committed to providing timely access to care but was dealing with thousands more presentations to the emergency department annually.
"As the Peel population grows and changes, we are seeing an increase in the number of older people and people with more complex illness requiring treatment in the ED," she said.
"The hospital is continually reviewing its processes in an effort to improve ED performance and in the past year it has introduced a number of improvements.
"Planning is now well underway for an upgraded ED that will improve patient flow and have a positive impact on hospital wait times, enhance patient confidentiality and privacy, and improve overall patient comfort and satisfaction."
Dawesville MP Zak Kirkup said he was concerned wait times at Peel Health Campus were getting "exponentially worse".
"It's a joke … we're getting left behind. People don't have time to wait when they're in the emergency department, that's why it's an emergency," he said.
After the federal government recently announced $25 million in funding to expand the ED, Mr Kirkup said it was time for the state government to "step up to the mark now".
"They're continuing to ignore us and these results are what happens - wait times and elective surgeries blow out, the hospital goes on bypass, we're on bed lock," he said.
"We're made to be second class citizens here because the state government is failing to act and it's not good enough.
"We need probably around $100 million for our hospital and what we've got so far from the state government is a pittance."
Mr Kirkup said he wants to see a hospital constructed to suit the "age and demographic profile" of the Mandurah community.
"We want a full plan for the future of our hospital that includes stroke and cardiac services that don't exist at the moment in Peel and a pacemaker technician," he said.