Police are searching for a teenage girl who is believed to have stabbed another teenager in the neck near Fountain Gate shopping centre in Melbourne's south-east.

A 16-year-old girl from Pakenham was flown to the Alfred Hospital in a serious condition after she was stabbed on a bike path along Magid Drive in Narre Warren just after 2:00pm (AEST) on Friday.

Police are looking for a teenage girl with a solid build and dark-coloured hair who was wearing a flannelette shirt.

She was last seen heading south, and police said she possibly ran into the shopping centre.

Detective Sergeant Shaun Allen said it was not yet clear if the victim and offender knew each other.

"It's just something that shouldn't happen," he said.

"We've got people going about their daily business and we've got a young girl now that's in hospital with serious injuries to her throat."

Police said a thorough search would be done of nearby properties on Friday evening.

Sergeant Allen urged anyone with information to contact Crime Stoppers.