Police have released a description of the woman whose body was found in an Auckland park this morning.

A homicide investigation has been launched and a post-mortem examination is underway.

The body was found at 6.50am behind the toilet block in Murphy's Reserve, Otahuhu.

The dead woman is Maori, in her mid-fiftites and of medium build. She was last seen wearing a long dark jacket and a multi-coloured jacket underneath, with dark trousers and black shoes.

"A scene examination is being conducted," said Detective Inspector John Tims. "The local Maori wardens are assisting police with the security of the scene.

"Police will be going door to door this afternoon and through the weekend to talk to the neighbours that reside around the reserve, looking for information that may assist the investigation."

Anyone who was in the reserve between midnight and 7am has been asked to contact Manukau police on 09 2950200 or call Crimestoppers anonymously on 0800 555 111.