Police have arrested a 23-year-old Mitchell Park man, who is in custody.

Paramedics were called to outside the Mitchell Apartments on Learmonth Road in Mitchell Park just before 3pm on Sunday. The apartments are a low-cost residential facility on the site of the former Gold Sovereign Motor Inn.

The girl, who had stab wounds to her abdomen and upper body, was taken to the Ballarat Base Hospital, where she remains in a critical but stable condition. 

Ballarat Police Senior Sergeant Neil Robinson said the stabbing was not domestic violence, with the girl and man unrelated to each other. However, police at the scene confirmed both lived at the apartment complex. 

There were not many other occupants around at the time of the attack and no details have been revealed as to what led to it.

"Police are currently conducting a door knock of the area in the hopes of speaking to witnesses," said Senior Sergeant Robinson.

SEE MORE PHOTOS FROM THE POLICE CRIME SCENE IN OUR GALLERY BELOW

He said the girl was stabbed with a "sharp-bladed instrument".

The man is helping police with their inquiries. 

Police say the interview with the man could take some time 'because of exceptional circumstances'. 

Residents of the apartments are believed to include people with disabilities.

Police cordoned off the driveway to the whole Learmonth Road estate, while two separate apartments within the complex were also barricaded.

Officers were seen taking photographs of the area, which was littered with children's play equipment.

Late Sunday evening, they were scouring a shared-use garden that sits in the middle of the complex, focusing on an area with a red twisting children's slide on the lefthand side.   

Mitchell Apartments, which is situated on a busy street, is owned by Catholic welfare provider Centacare.

The play equipment near where the girl was believed to have been stabbed.

A neighbour, who did not want to be named, said she no longer felt safe letting her children play out the front of her house.

"I felt sick and shaken," she said.

"If it's the girl I think, I've seen her and her mum ride past our house and back again.

"It doesn't make you feel very safe."

Her husband said many residents in the area hadn't wanted Centacare to open the apartments.

"It was meant to be for short-term, low income people, but I don't think that's who's in there," he said.

"Put it this way, we've been broken into twice since the apartments were there. I can put two and two together."

Another neighbour, Alison Schuz, said she also often saw the little girl riding past on her bike with her mum.

"It's terrible. It's very sad," she said. "I just hope the little girl is all right.

"They're pretty quiet and they just walk past, she rides her little bike."

Ms Schuz said it was the first she'd heard of trouble at the apartments, apart from a fire that destroyed a unit housing a young man with cerebral palsy in September.

"Everyone was against [the apartments] being built, but we hadn't had a problem up until now," she said.

Nearby residents voiced concern that the apartments might serve as cheap housing for parolees when Centacare applied to council for a permit in 2013.

At the time, local woman Mary Johnson said she hoped the area would not become home to parolees and "undesirables".

"If it's just low-income earners, then good on them," she said.

"But if it is for people who are coming out of prison ... the children (in the neighbourhood) won't be safe."

Bryce Hart said he would be concerned for his children's safety if the facility was turned into a temporary home for released prisoners.

Centacare project manager Geoff Wallace guaranteed, at the time, that the apartments would only be used as cheap housing. 

Police urge any witnesses to contact Crime Stoppers on 1800 333 000 or via www.crimestoppersvic.com.au

- The Courier, Ballarat, with The Age