Police have stepped up patrols in the Wellington suburb of Strathmore following arson attacks on two homes.
The first fire was lit in the outside laundry of a house in Tannadyce Street early on Saturday, with a second fire set in the same house that night.
A third fire was lit at a house in Sidlaw Street early on Monday.
Police believe the fires are linked because the occupants of the homes are related.
Detective Sergeant Todd, of Wellington, says the situation is concerning. Police want to hear from anyone who may have seen or heard anything suspicious.
Mr Todd says the people involved have no idea why they have been targeted.