Christchurch residents woke to a freezing morning without power after an unplanned outage struck parts of the city.

The outage, which began at 4.53am on Monday, affected 292 properties across Belfast, Harewood, and Northwood, leaving homes in the dark and cold as temperatures dropped.

Orion said the cause of the outage was still under investigation, but field staff were on-site patrolling the affected areas and working to restore power safely.

By 7.05am, 50 properties had been reconnected, with the rest expected to have power restored by around 9.56am.

The outage impacted residents on several streets, including Atap Place, Clearwater Avenue, East Stream Lane, Eminence Drive, Gardiners Road, Harts Creek Lane, Hebe Lane, Johns Road, Kaikainui Lane, Karos Lane, Manggis Street, Mayfly Lane, Rotoiti Lane, Stella Close, Tanjong Lobang Crescent, Waterview Court, and Waterway Lane.

Orion said it appreciated the patience of affected residents and would provide updates on its website as more information became available.