Western Australia's building regulator is investigating claims of defective firewalls at the new Perth Children's Hospital, as the construction union warns that replacing them could take many months.

Building Commission director of compliance Sandy Randall said the information came from an anonymous source about the construction and inspection of firewalls at the already-delayed project. “Building Commission inspectors are conducting a preliminary assessment of the firewalls to establish whether there is any validity to the information received,” Ms Randall…