They said the circumstances of the other fires “remain under investigation”.
A Fire and Emergency spokesperson earlier said they were notified of the first fire at a vacant building well ablaze on Harrow St, around 11.30pm.
Four fire trucks and a ladder truck arrived at the scene.
The fire was contained after midnight and extinguished at 3am, the spokesperson said.
Fire and Emergency received multiple calls of another fire at a Central Dunedin house around 12.30am.
Concerns that people were in the house were quashed after it was found empty, said the spokesperson.
Five fire trucks and a command unit contained the fire at 1.50am.
Around 1.30am, firefighters responded to reports of trees on fire near Otago Pistol Club in Waldronville.