Christchurch is taking stock after the magnitude 5.3 earthquake on Saturday.
It was the most powerful aftershock since 22 February, the day of the deadly magnitude 6.3 quake.
It occurred at 5.49pm, at a depth of 11km, about 10km from Diamond Harbour.
Civil Defence says 12 water pipe bursts are being repaired in the Lyttelton, Redcliffs, Mt Pleasant and Estuary Road areas.
Small pockets of these areas are temporarily without water and work is underway to restore water to these properties later in the day.
Water and storm water systems are working as normal.
Mayor Bob Parker urges people to conserve water.
The aftershock caused another round of liquefaction, but Civil Defence Controller John Hamilton says it is not as bad as the quake on 22 February.
He says it will take some time to see if there is any more damage to the sewer system.
Civil Defence advises residents to stay off the roads where possible, especially in the east.
There are problems with the phasing of traffic lights in the central city, so motorists should avoid driving there if at all possible.
Many Bexley residents spent the night shovelling silt out of their houses and yards once again.
New cracks appeared in the walls of some homes and some streets are flooded with sewage.
A number of people on Saturday night cited the latest aftershock as the 'final straw'.
There have been rockfalls in the Sumner/ Redcliffs area, but no new damage is reported there, apart from a burst water main.
Power back on
Power was cut to 20,000 customers around the city.
It was restored by 8pm, except to about 200 customers in Beckenham and Huntsbury affected by an underground cable fault. Their electricity was restored just after midnight.
Phone services were also disrupted for a time.
No injuries were reported.