Three shops have been severely damaged in a fire that has disrupted traffic on the Pacific Highway in Sydney's north.
Around 50 firefighters attended the blaze at Hornsby after a 2.10am (AEST) call-out on Wednesday.
Fire & Rescue NSW Superintendent Chris Jurgeit said a music shop/cafe was well alight when firefighters arrived.
They contained the blaze then extinguished it but three shops were severely damaged by fire.
Part of the Pacific Highway was closed to traffic on Wednesday morning.
Supt Jurgeit said it was not known how the fire started.
Fire authorities believe there was some kind of explosion at the Hornsby site but can't confirm if it caused the blaze.
"The windows were on the road, so something's blown them out," Supt Jurgeit told AAP.
"Our investigators will be finding that out during the morning."
Meanwhile, police are treating a fire at a smash repair business in Auburn in Sydney's west on Tuesday night as suspicious after firefighters put out the fire following a 10.30pm call-out.
