The dog, which police said was part pit bull terrier, ran inside a neighbour's house about 8pm in Lahy Street, St Albans, and savaged the girls and a 31-year-old woman.

Ayen Chol was pronounced dead at the scene despite ambulance officers efforts to revive her.

The five-year-old had facial injuries and the woman received severe lacerations to her arms and hands. Both were taken by ambulance to Sunshine Hospital, where they were each in a stable condition today.

Paramedics arrived at the house within seven minutes of an emergency call to find what team manager Brett Parker described as a very chaotic scene.

‘‘A four-year-old girl was in the house and had suffered extensive injuries,’’ Mr Parker said.

‘‘Paramedics tried to resuscitate the girl but, unfortunately, she died at the scene.’’

Police last night said they had spoken to the dog's owner, a 30-year-old man from a nearby house. Brimbank Superintendent Graham Kent said there was the potential for charges to be laid against the owner.

Superintendent Kent said the aftermatch of the attack inside their victims' house was distressing.scene.

''This is a really horrible tragedy and it will take some time for us to fully understand what happened,'' he said.

The dog was back on its owner's property when police arrived. Shortly before midnight last night, council workers took the dog away in a van. Police said it was likely to be put down.

Earlier, about 30 people, including several children wrapped in blankets, gathered in the quiet suburban street, which had been cordoned off by police after the attack. Some of the people embraced each other while others sobbed into mobile phones. One woman was wailing hysterically.

A relative, Daniel Atem, said the dead girl was the youngest of three children and had two brothers aged nine and 12. He described her as ''a lovely little girl, very talkative and popular in kindergarten''.

Mr Atem said Ayen had been living with her brothers and her mother at their cousin's house at the time of the attack. Their previous house had burnt down last month.

The girl's father, Mawien Chol, was in South Sudan, having left Melbourne to join independence celebrations, he said.

The family is believed to have arrived in Australia in 2004 after spending three years in Egypt awaiting resettlement.

Only last Saturday, police used capsicum spray to subdue a pit bull terrier that had savaged an elderly woman’s Scottish terrier in a Ballarat Street, then turned on two men who intervened.

The last reported fatality involving a dog attack in Victoria was in 2007, when a nine-week-old girl was dragged from her cot and mauled by a pet rottweiler. She died from severe head and neck wounds.

Penalties for an owner or person in control of a dog that attacks or bites any person depend on the seriousness of the attack and whether the dog had been declared to be dangerous before the attack began, according to Victoria Legal Aid.

In March last year, the owner of an unregistered Siberian husky that savaged a then 22-month-old girl was fined more than $6000.

In Victoria, according to a council survey taken about four years ago, there were said to be about 3300 dog attacks reported in one year.

- with Megan Levy