Police are appealing for help from the public after a spate of suspicious fires in Piha this week.
Detective Sergeant Ashley Matthews said the fires occurred on Monday night and early this morning at the West Auckland beach.
"Police were informed of a number small scrub fires on the Tasman View Track at Piha on the night of Monday. The track starts at the southern end of the beach leading to a lookout above Camel Rd, then continues onto the Hillary Trail.
"Police were then alerted to another spate of fires in the early hours of [today] on the Marawhara Walk Track at North Piha. Not long after these fires were lit, fire crews became aware of two more fires on Lion Rock and another on the embankment at the intersection of Marine Parade South and Beach Valley Road."
Police believe the fires were deliberately lit one to two hours either side of midnight on both occasions and believe they are all likely related, Matthews said.
"These fires are a destructive and senseless act of vandalism and police will work to hold to account whoever is responsible. We are conducting scene examinations with the assistance of fire crews and are making further enquiries today.
There will also an increased police presence in the area.
Anyone with information about the fires, or who may have seen anything suspicious should contact Detective Sergeant Mike Clubb, of the Waitakere CIB, on (09) 837 9511.
Alternatively, Crimestoppers can be called anonymously on 0800 555 111.