A woman has died in hospital after stumbling into a Dome Cafe in Perth's southern suburbs with serious neck injuries from an alleged assault.

The WA Police Homicide Squad is investigating the death of the social worker, who managed to drive herself to the cafe on Kent Street in Rockingham to get help about 6:00pm on Saturday night.

She was taken to Fiona Stanley Hospital where she later died.

Police have arrested a man in connection with the incident but no charges have been laid.

Flowers were laid outside the cafe in Rockingham after the woman's death. ( ABC News: David Weber )

It is understood four cafe staff members who were working at the time did what they could to help, calling an ambulance for the desperate woman.

The Australian Association of Social Workers (AASW) released a statement offering its condolences over the woman's death.

"We extend our deepest sympathies to everyone affected by this tragedy," AASW president Christine Craik said.

"We can't comment on the specifics of this case at this time, but all social workers have the right to be safe as they go about their jobs — and it is especially hard to understand this kind of violence towards any worker who is there specifically to help and assist.

"We know from published research, that the majority of social workers will experience violence from clients at some stage in their careers.

"Better resourcing of the sector is much needed."

Counselling for cafe staff

Dome Group managing director Nigel Oakey said the cafe remained closed on Sunday while police continued their investigations.

Cafe workers tried to help the woman and called an ambulance. ( Supplied: Night News )

"Staff at the Dome cafe in Rockingham rendered assistance to a female who entered the cafe with significant injuries," Mr Oakey said.

"The injuries were not incurred at the cafe or in the immediate vicinity and the person arrived seeking urgent medical attention."

Mr Oakey said counselling had been arranged for staff members involved in the "traumatic incident".

"Our thoughts are with all those affected by this incident," he said.