A violent knife attack on a cleaner in an Adelaide shopping centre has come after years of concerns for the safety of workers at the northern suburbs venue, a union says.
The 30-year-old woman was attacked on Monday night in a toilet at the Parabanks Shopping Centre by a man armed with a knife.
She suffered serious injuries to her face and is being treated in the Royal Adelaide Hospital.
Police have described the incident as disturbing and have called for public help to identify the offender.
The retail sector union said it had previously urged centre management, the council and police to review safety at the centre.
Assistant secretary Josh Peak said safety at Parabanks had been an issue for workers for years.
"We've received accounts of workers being assaulted, followed, threatened and robbed in and around the Parabanks Shopping Centre and car park," he said.
"We're calling on centre management to introduce tougher security and safety measures in the car park including better lighting and more security guards and more CCTV cameras."
Detective Inspector Naomi Oberscheidt said police were following a number of lines of inquiry and were keeping an open mind on the possible motive.
Police Minister Corey Wingard said it was inappropriate for him to comment while the matter was under investigation.
He said safety concerns at Parabanks had not been brought to his attention.