Police remain baffled as to how a woman and man fell 10 metres from a Melbourne apartment complex.

The death of the woman who plunged from the Collingwood apartment balcony is not being treated as suspicious.

The couple was discovered about 11.30am on Saturday after plummeting from the Smith Street complex.

The Abbottsford woman, 29, died at the scene and a 35-year-old Collingwood man remains in the Alfred Hospital in a stable condition.

Victoria Police say they will prepare a report for the coroner and are still investigating the exact cause of the fall.

Witnesses are asked to phone Crime Stoppers on 1800 333 000.

With ABC