The Australian Medical Association says the situation at Perth's Fiona Stanley Hospital on the weekend was unacceptable, as hot water and central heating were shut off during repairs.

Extra rugs and heaters were handed out to patients during the work to fix a major water leak, which was completed late on Sunday morning.

It is the second big leak at the new hospital in the space of just three months, and WA Health Minister Kim Hames has conceded they may continue.

Surgery was called-off for the weekend and ambulances were diverted, except in serious emergency cases.

The hospital has issued a statement saying all operating theatres were now back online, and the ambulance and maternity diversions resumed late on Sunday morning.

Dr Hames says the government is not to blame for the problems, which are the subject of an ongoing investigation.

The health minister said he hoped the Health Department would get some answers at a meeting with builder Brookfield Multiplex on Tuesday.

The Australian Nursing Federation said the government needed to sort the problems as soon as possible.

But the nursing body said morale was still high among staff, many of whom are excited to be working at the new hospital.