Detective Superintendent Barry Vincent said the initial triple-zero call was made at about 11.45pm, but there was no communication from the caller although “raised voices” were reported.

Triple zero attempted to return the call twice but did not make contact.

NSW Police called the same number at 11.47pm and spoke to a man who confirmed his name and address, Vincent said, and police told him they would attend the premises but did not give a time.

Police were attending other calls for assistance en route to the address when they received a call from somebody standing in the street on River Road in Parramatta who said they saw a woman hanging from the seventh-floor balcony of a high-rise unit block.

That call took place at about 1.40am and Vincent said police were on the scene by 1.41am, where they discovered a woman in the driveway of the unit block with critical injuries.

She was unable to be revived and died at the scene.

The woman, believed to be aged 39, is yet to be formally identified.

Police confirmed they had arrested a 40-year-old man they allege had been the woman’s partner.

Vincent said police had confirmed the man they spoke to on the phone was the same man now under arrest.

The residence the woman had fallen from was his, while she was believed to reside elsewhere.

Vincent said police had previous interactions with the pair, though he did not know if they were in a current relationship.

He said the man had an AVO in place for his protection, but pending identification of the 39-year-old woman, it could not be confirmed if the same AVO involved her.

Anybody with information is urged to contact Crime Stoppers on 1800 333 000.