An inferno in two buildings that threatened the famous Nylex clock site in inner-Melbourne could trigger the closure of a Citylink on-ramp for several days.
Firefighters were called to the suspicious blaze in Cremorne just after midnight and crews arrived in less than six minutes to find the fire quickly spreading through the two disused buildings.
About 60 firefighters, 10 pumpers and three aerial units were called to the fire.
"Crews conducted an external attack on the fire and used aerial appliances to reduce the blaze. The fire was declared under control at 2.05am," the MFB said in a statement.
Victoria Police say the exact cause of the fire is unknown and it is being investigated as suspicious.
"While the fire has now been brought under control, road closures are expected to remain in place for the coming days at the Punt Road on-ramp to Citylink while works are undertaken to repair the structure," police spokeswoman Natalie Butler said in a statement.
Owners and developers of the site, Caydon, says it has installed security measures to prevent trespassing and will be working with authorities in their investigations.
"The scale, configuration and heritage restrictions of this unique site presents numerous challenges, and it is impossible to completely prevent unwanted access from those determined to access the site," they said.
"This is why we are anxious for planning officials to issue permits so development can commence.
"We regret any inconvenience the fire may cause residents and commuter traffic, and are working with all authorities to make safe the site and its surrounds."