Police have shot and killed a man armed with a samurai sword after he held four young children and two women hostage in a home on Brisbane's southside on Monday.

Emergency services were called to Cassowary Street in Doolandella, 22 kilometres south-west of Brisbane CBD, about 5.30am after a disturbance involving the deceased.

Inspector Tim Partridge said the incident developed into a siege when the man took four young children, all under the age of 10, and two women hostage inside the home.

Inspector Partridge said one of the women held against her will was the children's mother and the other was a housemate. It is believed the deceased lived at the home.