Construction on the Peel Health Campus' emergency department upgrades have been delayed due to concerns of a potential coronavirus outbreak.
Works were expected to begin on Tuesday afternoon but will instead be deferred for two weeks, subject to review.
Premier Mark McGowan said the decision was made to ensure the capacity of the emergency department would not be reduced during the coronavirus "crisis".
"You have to close off part of [the emergency department] while you do the work... in doing so, there's a disruption," he said.
"We've deferred that work until such time as we're passed this crisis."
The state government has pledged $9.4 million to PHC since being elected in 2017, with $5 million of that to reconfigure the emergency department.
The upgrades will include a new fast-track area to improve patient triage, new holding bays, a reconfiguration of the existing triage area and a redesign of the waiting room, as well as the addition of seven short-stay beds to streamline patient flow.
Mr McGowan confirmed construction, which was scheduled to be completed by August 2020, will still go ahead when the timing is right.
"The work will happen," he said.
"It's just that we want to make sure we maintain the maximum emergency department capability for the public during this period of time."
WA Health Minister Roger Cook described the decision as a precautionary and temporary measure.
"The upgrades to the Peel emergency department was basically tools ready," he said.
"The Department [of Health] has asked the contractor to wait a fortnight while we review the situation and see what we need to put in place to protect the capacity of the emergency department.
"That includes other ways we can use the hospital site to make sure that we still have that capacity.
"We need to ensure we have not only physical capacity but work force capacity as well.
"In the short-term, we've decided to postpone those works at least by a fortnight until we can make that decision."
Mr Cook added that Peel Health Campus would be the only hospital affected by the decision to postpone construction works.