A homeless man trapped underneath a Melbourne pier has told his rescuers he was there for at least five days.
A specialist Metropolitan Fire Brigade crew rescued the man from the Docklands pier at about 9.30am on Thursday after passers-by heard his cries for help.
MFB Commander Rick Gili said they don't know how the man managed to get underneath the pier or how long he had been there.
"He was sitting crouched on a ledge, a supporting beam of sorts, but he wasn't in a good way mentally or physically," Commander Gili told AAP.
The crew had to coax the man, who appeared homeless, from the ledge and onto the rescue boat.
"When we got him on the boat, he could barely stand up and couldn't walk, he was desperate for a drink.
"It appears he had been there for some time."
The man told his rescuers he had been there for between five to 12 days, Commander Gili said.
"I don't think he would've made it there for much longer, the water was freezing," he said.
The man was taken to hospital for a check-up but does not appear to be seriously injured.