Police are investigating a cluster of fires in the Christchurch suburb of Avonside which broke out in the early hours of Tuesday morning.
Four fires occurred between 4.30am and 7.15am.
Two were in vacant houses, a third was in a garage adjacent to a vacant property, while the fourth was a vegetation fire.
Acting detective senior sergeant Stewart said police are seeking information from the public about any suspicious activity seen in the Avonside Drive, Keller Street and Retreat Road area on Tuesday morning.
He said police are also interested in any information about a van seen in the area around the time of the fires.