A five-year-old girl is in a critical condition after being stabbed multiple times in Ballarat.

Police said the girl was stabbed outside an apartment building in Mitchell Park just before 3:00pm (AEDT) on Sunday.

She was wounded in a number of areas including her upper body.

A 23-year-old Mitchell Park man was arrested and was assisting police with their inquiries.

The girl was taken from the Learmonth Road complex in a critical condition to the Ballarat Base Hospital.

Ballarat Police Senior Sergeant Neil Robinson said the man and the girl were not related and the stabbing was not a result of domestic violence.

"There is no family relationship or anything like that, the relationship is merely one of being neighbours," he said.

"At this stage, the latest information we have is that the prospects of the little girl are looking promising.

"We've spoken to a number of people, but we'd like to hear from anybody who may have seen or heard anything."

Officers from the Ballarat Crime Investigation Unit have urged anyone with information about the incident to contact Crime Stoppers.