Health Minister Steven Miles says no patients have been exposed to unsterilised equipment at Brisbane's Princess Alexandra Hospital.

All but the most pressing operations have been cancelled.

"Due to a malfunction with the sterilisation equipment, the Princess Alexandra Hospital is only conducting emergency and urgent elective surgery today with reserve sterilised equipment," the minister said on Friday.

"As always, patient safety is the priority. I have been advised that no patients have been exposed to unsterilised equipment."

Health authorities have not elaborated on the malfunction but technicians are urgently trying to fix the situation.

The hospital's emergency department remains open and is accepting patients.

It is not known when the problem emerged but staff have told the ABC they noticed rust on some equipment earlier this week.

Opposition health spokeswoman Ros Bates said the minister needed to fully explain what went wrong, saying patients, their families and staff would be feeling stressed.

Australian Associated Press