Legionella outbreak could delay Perth Children's Hospital opening

There are fears the long-awaited opening of the Perth Children's Hospital could be pushed back, with a second outbreak of deadly Legionella bacteria discovered on site.

The $1.2 billion facility is due open its door in just nine days' time - on May 15 - after more than two years of delays.

This latest blow comes after the ongoing lead contamination water issues had finally been overcome.

In an email sent to senior staff on Friday, Child and Adolescent Health Service chief executive Robyn Lawrence revealed that testing of samples collected on April 16 had detected Legionella in 45 out of 100 sampled locations that were "above the desirable levels".

Dr Lawrence said immediate steps were being taken to resolve the issue, including temporarily turning off the water supply to intensively treat the water.

Bottled water will be supplied to staff until water is confirmed to be safe.

In October last year, Legionella was detected at the hospital, with testing finding 14 instances of the bacteria in water outlets, a shower head and a drinking fountain.

In her email, Dr Lawrence reportedly said the hospital's opening schedule would remain the same at this stage, but the situation would be reassessed early next week.

Perth Children's Hospital was originally meant to open its doors in 2015.