Millions of Optus customers are being affected by a nation-wide outage.
From early Wednesday morning, phone users were unable to make or receive calls, or use the internet on Optus’ mobile network.
Ramsay Health Care says their hospitals are being affected by the outage including Peel Health Campus in Mandurah.
They are asking anyone who needs to get in touch to fill out a contact form on the local hospital's website.
Optus chief executive officer Kelly Bayer Rosmarin told ABC Radio, they are working to restore services.
"The team has tried a number of parts of restoration and so far we have not had the results that we have hoped for. And we're pursuing every avenue to get everybody back online as soon as possible," Ms Bayer Rosmarin said.
"We're really really sorry that this outage has occurred and we're working to restore services for our customers as a priority.
"The teams are trying many different angles and we will not rest until the service is back up for our customers."
Ms Bayer Rosmarin said they are still unsure what caused the outage.
Customers who need to contact emergency services will still be able to call 000 on a mobile line but will not be able to on an Optus landline.
Optus are yet to reveal a restoration time.