An investigator is at the scene a serious house fire in Christchurch, which spread plumes of smoke across the city on Friday morning.

Crews from the Christchurch City, Spreydon, Anzac, and Woolston stations were called to the fire which ripped through a property on Grenville St in Waltham about 7.20am.

A Fire and Emergency NZ spokesperson said the blaze was already well involved when crews arrived and they were working to extinguish it.

They confirmed a fire investigator had since arrived at the property to determine the cause of the blaze.

Fire crews at the house fire on Grenville St, Waltham. Photo: Geoff Sloan

Police cordoned off the area and Grenville St was partially blocked for a time.

There were no reports of injuries at this stage.

Multiple crews were called to the house fire on Grenville St in Waltham. Photo: Geoff Sloan