Christchurch police are seeking information on a series of fires in the Wainoni area early this morning.
Police were called about 2.15am when a resident reported an excavator parked on Buckleys Rd, near Bromley Park, had been set alight.
Police said the offender or offenders broke into a fenced area off the roadside to reach the machine.
The cab of the excavator, which was being used to repair sewers, was severely damaged by the fire.
About an hour later, a van and a car in Vancouver Crescent were set alight and substantially damaged.