'Fierce' fire destroys Sydney business

Firefighters have worked to save a row of shops and businesses after an office went up in flames in Sydney's west.

Twelve fire trucks were called to Boomerang Place in Seven Hills at 2.35am on Thursday, with crews battling to save adjoining shops from the inferno, which spread from the top-level office.

An investigation was underway to determine what sparked the fierce blaze, a fire brigades spokesman told AAP.