Christchurch police say they are confident recent arsons across the city are not linked and are likely to have been the work of opportunists.
Six suspected arsons have occurred in the past fortnight but police say overall levels of reported arson across the city are no higher than normal.
Detective Inspector Greg Murton says investigations into recent suspicious fires show they are likely to have been the work of different people and are mostly opportunistic incidents.
Detective Murton says the fires are occurring across the city, not just in abandoned properties in the residential red zone.
The police are calling on people to be extra vigilant and report any suspicious activity.