Investigations are underway into a suspicious blaze in the central Christchurch suburb of Sydenham.
The fire service was called to the scene on Stanley St at about 11pm on Friday.
Southern fire service shift commander Andrew Norris says the building was well alight on arrival.
"The fire took about three hours to extinguish [but] there were no injuries or anything like that.
"There were some initial concerns that there may have been some squatters staying in there - so from that I would say the building was possibly unoccupied [by residents or a business]."
Mr Norris adds there was initially some risk the blaze could spread to neighbouring buildings, but this was mitigated by fire crews.