On the Ngunguru Rd fires, he said a vehicle was seen with people firing firecrackers out the window before the fire started.
He was not in a position to release more information, including whether all the four fires were related and possibly started from firecrackers.
Martin reiterated earlier warnings for people to be more responsible around lighting fires, especially at this time of the year.
Firefighting resources were stretched during all four fires.
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Ngunguru fire brigade station officer Chris Gibbs said two appliances were sent to put out the biggest of the three fires on Scow Landing around 5.30pm on Sunday that torched about 300sq m of mainly gorse and pampas.
At the same time, he said fire crews from Whangārei, Kamo and Hikurangi were dealing with the other two fires along Ngunguru Rd.
On Saturday, Whangārei firefighters were attending to an escaped control burnout on Harris Rd in Glenbervie when the Abbey Caves Rd fire was notified to emergency services.
The blaze forced the closure of tracks used and maintained by the Whangārei Mountain Bike Club's 80 members.
Quick action by fire crews from Onerahi and Kamo that were the first on the scene removed the initial threat on two houses.
Crews will be at the scene for the next couple of days to ensure there are no flare-ups.
There are significant hotspots but the fire is well contained.
Early this year, Fire and Emergency NZ spent more than $320,000 fighting four major scrub fires alone in the mid and Far North.
People can check their local fire status at checkitsalright.nz