Police are investigating the death of a woman in an apartment in Sydney's east this morning.

They were called to a unit at North Bondi at 9:20am this morning where a woman was reportedly found unresponsive.

When paramedics and police officers arrived, she was unable to be revived.

Police are yet to formally identify the woman but she is believed to be 19 years old.

The ABC understands the woman had no obvious injuries and police are waiting for the results of an autopsy before determining how she died.

A 32-year-old man was arrested at the home on an outstanding warrant and is assisting police with their inquiries.

Police sources say the pair were in a relationship and had been living together at the property since last year.

The man has been arrested on an unrelated outstanding warrant and has not been charged over the woman's death.

A post-mortem will be conducted to determine the cause of the woman's death.