A man has had a lucky escape after being dumped into the back of a rubbish truck in Perth's central business district.

The man was in a skip bin on St Georges Terrace when it was picked up and the contents dumped into the back of the truck just after 4:00am (AWST).

It is understood the man's screams alerted the driver.

He has told authorities that he was in the bin looking for his laptop computer.

Firefighters helped rescue the man and say it is lucky he was able to alert the driver before the rubbish was compacted.