A manhunt is underway and police are appealing to the public for information.
At the homicide scene on William Blofield Ave, Inspector Kerry Watson confirmed the stabbings had occurred at a gathering late on Friday night.
A witness said what appeared to be a body could be seen lying on the road in front of a police car.
The party was in a residential street, in an aging state housing subdivision between Wesley Intermediate School and the south-western motorway.
Officers at the scene had arrested and cuffed a man, a bystander said, though the arrest was not thought to be directly related to the stabbing.
Around the corner on Denny Ave, paramedics assisted a person with serious stab wounds. Inspector Watson said the person was taken to hospital in a serious condition.
Police communications staff confirmed criminal investigations detectives were investigating the incident in Mt Roskill. Watson described it as “a large scene”.
Police said there were people helping with inquiries, but they appealed for help from any other members of the public who had information or had seen anything.
Detective Senior Sergeant Glenn Baldwin is expected to lead the investigation and further updates are expected in the morning.
Sunday Star Times