"Lives were not put at risk, although there are always risks involved in fighting any fire, but these arsons are costing the community dearly," he said.
"Not only is there a cost in terms of the volunteers' time, much of it given when they would otherwise be at work, but town water doesn't come cheap either, and a lot of water went on to this fire.
"Then there is the potential loss of jobs. The owner of this mill had been talking about getting it working again, and using it to train people in the milling industry, but I imagine that chance has gone now. All in all, this hasn't been a good day for Kaitaia."
A pattern was beginning to emerge and Mr Kerrisk had no doubt someone would know who was responsible.
"Someone will have the information we need to get to this person and see that they get the help they need," he said.
He asked members of the public with information about the fire, or those responsible, to contact Detective Sergeant Trevor Beatson at 09 4086500, or Crimestoppers on 0800 555-2111.
Fire Service arson experts and business analysts were examining all recent fires in the greater Kaitaia area, collating data such as the day of the week and hour of the day that they were lit, to see if any connections could be made, and passed on to the police.
Mr Kitchen, meanwhile, noted that once again arsons tied up resources that could be needed elsewhere.
The blaze had not been easy to fight - the last firefighters did not leave the scene until 1pm, and the site was kept under surveillance for hours after that - but the crews had done well under difficult circumstances.