A man was in custody on Thursday after sparking a bomb scare and being detained by car wash workers in inner Melbourne.

Police were called to Racecourse Road at North Melbourne, near the intersection with Flemington Road, about 10am after a man was found with an unknown device.

The 25-year-old man was arrested and was being interviewed on Thursday afternoon.

“Police are currently at Racecourse Road in North Melbourne after a man was located with an unknown device about 10am,” police said.

A police robot was used to inspect the device. Photo: AAP

Businesses in the surrounding area were evacuated, while Racecourse Road was closed to traffic and trams between Flemington Road and Boundary Road while the bomb response unit conducted safety checks for about two hours.

The area was given the all-clear about midday.

Witness and carwash worker Abhi Mohan said the man was seen trying to steal a car and he and his colleagues started yelling at him.

“We all got into him and we took him into the garage and then I called the police,” he said.

Mr Mohan said the man appeared drug-affected and was saying his dad had cancer and he wanted to “borrow” a car.

When police arrived, they looked at the man’s bag and what they saw inside sparked the bomb scare, Mr Mohan said.

-with AAP