Old Melbourne paper mill fire deemed 'suspicious'

A suspicious fire at a disused paper mill has played havoc with peak hour traffic trying to use one of Melbourne's most congested roads, Chandler Highway.

The fire at the old Alphington paper mill is being investigated by police after firefighters were called about 4.10am.

The building was not occupied and no injuries were reported but the Chandler Highway was closed for three hours - only reopening at 7.30am.

Investigations will continue at the scene today, with authorities treating the fire as suspicious.