The death of an elderly man in a Christchurch aged care facility after yesterday's second big earthquake may not be quake-related, say police.

Geoff Hipkins, chief executive of aged care provider Oceania, confirmed the man died in the Resthaven home in the suburb of St Albans early today.

The 88-year-old man fell during yesterday's 2.20pm 6.3 magnitude quake and lost consciousness.

Mr Hipkins said the man was seen by a doctor and seemed to recover, but died during the night.

Tonight police said the death had been referred to the Coroner but may not be directly related to yesterday's earthquake.

"This elderly local gentleman did have a number of health issues however the cause of his death is yet to be determined," Superintendent Dave Cliff, Canterbury police district commander, said.

"It is not necessarily linked to the earthquake."

Mr Cliff said full policing services continued across the city.

Reassurance patrols staffed by out-of-town officers had been active in the eastern suburbs and hills areas, knocking on doors, helping people out including shovelling silt.

"We've been checking on the wellbeing of residents, helping people remove silt or belongings and undertaking traffic patrols to ensure people are as safe as possible."

Mr Cliff said traffic around the city had been generally well behaved and people were taking advice to stay off the roads unless required to travel.

"Police urge everyone to continue to take care on earthquake damaged roads, keep an eye out for pedestrians and cyclists and be safety aware. Several roads and bridges remain closed, and liquefaction, boulders and holes are present on many streets," Mr Cliff said.

- NZPA