Homicide detectives are continuing to investigate the mystery death of a WA woman, who was found floating in a fishing harbour.

Forensic officers and homicide investigators descended on Fremantle Harbour on Sunday after a member of the public made the grisly discovery about 5am.

WATCH THE VIDEO ABOVE: Police investigate after woman’s body found in harbour.

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Police confirmed the woman had been identified, but are yet to release any information on her age and where she lived.

Whether she was injured and how she ended up in the water are also yet to be revealed.

Investigators cordoned off part of Cape D’Angelo Drive for most of the day as officers scoured the scene.

Homicide Squad Detective Senior Sergeant Greg McDonald said the water added a challenging element to the investigation.

“The circumstances in which she was found raise significant concerns for the police who were called,” he told reporters.

“We believe the circumstances surrounding the lady’s death and her location in the harbour raised suspicion, and the homicide squad are investigating at this point.”

Police could not confirm how long the woman had been in the water for.

McDonald said the woman’s recent movements would be significant to police piecing together how she died.

The harbour is controlled by the Department of Transport, which told 7NEWS it has handed its security video to police.

Anyone with information is asked to contact Crime Stoppers on 1800 333 000 or report online at crimestopperswa.com.au.