Overall levels of reported arson across the city were no higher than normal.
"We are seeing suspicious fires occurring right across the city - not just in the residential red zone,'' he says.
"However, vacant homes are always a potential target for arsonists, so we are alert to the risks around red zone properties.
Of around 60 suspicious fires across the greater Christchurch area in the past three months, most had been things like wheelie-bin fires and vegetation fires.
"And of all the reported incidents, fewer than one-third were in residential red zone areas. Overall, the rate of suspicious fires at present is no higher than historical averages,'' he said.
Police were working with the Canterbury Earthquake Recovery Authority and the Fire Service to identify risk areas where properties were being vacated and to take preventive measures.
"We are stepping up our preventive work as the number of vacant houses increases, including increasing our patrols through areas where homes have been vacated,'' Mr Murton said.