Suspicious fires continue to be lit in Palmerston North, though police say they have arrested a 25-year-old man for two arsons earlier this year.
The arrest overnight was not related to a number of arson fires in the city early last week and another last night, which police were still investigating.
The man was due to appear in the Palmerston North District Court today, charged with arson related to fires lit at the junior football clubrooms and Hokowhitu School grounds in February, said Sergeant Gary Milligan.
The latest suspicious fire was lit just after 8pm yesterday at a half demolished house in the suburb of Hokowhitu, said Palmerston North Fire Service senior station officer Graeme Mills.
Firefighters were able to control the fire within 10 minutes but one room was "gutted", he said.
Police and fire safety officers were investigating today.
"It's definitely suspicious but too early to say if it's linked to the others in the city," Mr Mills said.
Police have a suspect for the series of arsons and have released CCTV footage showing the man starting one of the seven blazes around the city.
He was seen lighting a fire at the Esplanade Cafe near the city centre early on Wednesday morning last week.
He is described as having short cropped hair and wearing a jacket with reflective strips on the shoulders. He was also carrying a bag on his back.
Sunday a week ago fires were lit in the same area, north of the city centre.
They were in a skip at Skoglund Park, a caretaker's shed at Terrace End School, a construction site by the Leisure Plex on Railway Rd and a tractor shed at Freyberg School.
The tractor shed contained a van used to transport children with disabilities.
Three further central city fires were lit last Thursday at a cafe on the Esplanade, a takeaway and dairy on Cook St and the Farmers construction site on the corner of Church Street and Ashley Street.
The sites were less than 2km apart.
Police were working their way through a list of five or six people "nominated" to them.