A 49-year-old man has been charged with arson and is due to appear at Christchurch District Court tomorrow.
A fire communications spokesman said the property is almost completely destroyed.
Police are now seeking witnesses in the Worcester St-Stanmore Rd intersection area prior to the fire.
Anyone with any information should call Christchurch Central Police Station on 03 363 7400.
Information can also be provided anonymously by calling Crimestoppers on 0800 555 111.
Police added that with the extremely warm and dry weather in Canterbury, the fire is a "timely reminder for owners of vacant buildings to make sure they are secure and not being used illegally".
Police and the Fire Service urge members of the community to report smoke or fire as soon as possible by calling 111 to prevent unexplained fires getting out of control and causing considerable damage and potentially loss of life.