A man was discovered living in a crawl space of a home near Portland, Oregon without the owner's knowledge, authorities say.

The man had been living there for an extended period of time, having set up a bed and lights, the Clackamas County Sheriff's Office said.

The owner told deputies no one should be living there and they had heard "strange noises" coming from the space before.

Deputies found 40-year-old Beniamin Bucur inside the crawl space and arrested him on charges of burglary and unlawful possession of methamphetamine.

Late on Wednesday evening local time, a witness reported seeing a man they did not recognise parking his car and walking towards the back of a housing complex close to Happy Valley, a small city southeast of Portland.