A fire that broke out overnight in the roof of St Paul's Cathedral in Dunedin has been brought under control but crews are still working to extinguish it.

Flames emerge from the roof of the cathedral in the early hours of Tuesday morning. Photo: Otago Daily Times / Stephen Jaquiery

Firefighters were called to the Anglican cathedral at the corner of Moray Place and Stuart Street about 3.30am.

Seven fire trucks and a command unit were called to the central Dunedin church.

Crews using a large crane fought the flames from above.

A crane at St Paul's Cathedral in Dunedin where the fire broke out in the roof overnight. Photo: RNZ / Tess Brunton

Police were also at the scene.

Fire and Emergency southern region shift manager Andrew Norris said accessing the roof had been challenging.

"They've been working with the turntable ladder to access and extinguish the fire, supported by crews within the building," he said.

There was no immediate update on the extent of the damage, however Norris said there were no injuries.

The scene of the fire. Photo: RNZ / Tess Brunton

There are some road closures and traffic diversions around the site.