Detectives are investigating after a body was found in a northern suburbs park on Wednesday afternoon.

The body was located in Mawson Park lake in Hillarys at about 4.30pm with a huge police presence quickly descending on the park.

Several unmarked police cars have their lights shining on the lake as forensics scour the edges with torches and take photos of the scene.

Police were still working to recover and identify the body at 9pm.

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The circumstances surrounding the death are unknown at this stage.