A 19-year-old woman has been sexually assaulted in her Clayton home after waking to find an unknown man in her bedroom.

Detectives from the sexual crimes squad have been told the attack occurred about 5.25am on Saturday, April 9.

Police wish to speak to this man, but have said there is no information to suggest he is a suspect.

A Victoria Police spokeswoman said the victim had been sleeping in bed but woke up to see a man in the room.

"The man made threats and demanded cash before sexually assaulting her," Acting Sergeant Melissa Seach said.