New Brighton Police are seeking information anyone in the area of the fire, or who may have witnessed people or vehicles in the New Brighton mall area on Seaview Road or Beresford Street between the hours of 12.30am and 2.00am. Anyone with information should contact Detective James Haigh on 03 3739118.
The New Brighton fire was followed by suspicious fires in Pines Beach, near Kaiapoi, and Heresford St in central Christchurch.
Meanwhile an abandoned house in Oxford was gutted by fire this morning, although the blaze is not thought to be suspicious.
A Fire Service spokesman said crews were called to the fire, on York St, about 1.40am.
Two trucks were called to the house, which was well ablaze on arrival, he said.
The fire was extinguished about 2.50am, and fire safety are investigating the cause of the blaze.