Four Huntly businesses were damaged after fires were set at the rear of the buildings in the central business district on Saturday night.
Another property was damaged on Sunday afternoon by a fire set in a similar way at a shop.
Waikato police said they are seeking information and help from the community.
They would like to hear from anyone who may have seen people in the area of the Venna Fry Lane around 8pm and 10pm on Saturday, and/or between 2pm and 5pm on Sunday.
