A fire at commercial premises in Christchurch early this morning is not thought to be suspicious.

Fire and Emergency crews were alerted to the blaze in a shop unit, on Pilgrim Ave, near Moorhouse Ave, about 3.30am.

Two crews were initially sent to the scene, but additional calls from members of the public reporting the fire led to two more crews being dispatched.

The fire was well involved when the first crews arrived and was still under control just under a hour later.

No one was inside the building at the time of the fire.

A fire investigator was expected to attend later this morning.