A 21-year-old man has handed himself in over an alleged sexual assault in a Thornbury park on Saturday night.

The man, of no fixed address, attended Preston Police Station on Monday morning.

He has been charged with rape, false imprisonment and theft, and will appear in the Melbourne Magistrates’ Court on Tuesday.

The arrest relates to the alleged sexual assault of a 32-year-old woman in a park on Leinster Grove about 10.30pm.