Police remain at the scene and will stay there into the evening to complete a scene examination.
Detective Senior Sergeant Armstrong thanked the public for their assistance and urged anyone with information to contact the Operation Pompano investigation team on 09 302 6557.
Earlier today, a witness said the attack happened outside the entrance to the Wilson Parking building at about 2.45pm.
Employees from a nearby store said they heard a woman screaming. They then heard a man screaming but didn't leave the store because they were attending to customers.
Bystander Abhi said he saw a woman lying down on the ground.
"I spoke to one of the ladies who witnessed it all," Abhi said.
"She told me it was a white guy, a tall guy, with some kind of kitchen knife in his hand. She saw him stabbing her in the back and in the front.
"All I saw was a lady lying down, we all went to see what's going on," the witness told Abhi.
Members of the public rushed to the woman's aid and tried to help with basic first-aid supplies. Police and ambulance officers arrived soon after.
When the Herald went to the scene this afternoon the woman's handbag and other personal items were still on the footpath.