Gale force winds forecast for Sunday for Canterbury are also set to spread to other parts of the country.
A deep low crossing the Tasman is due to reach Canterbury around mid-morning, bringing high winds that may cause further damage to property.
Heavy rain warnings have been issued for Monday in the west of the South Island, the Southern Alps, the Tararua Ranges and Mount Taranaki.
Severe northwest gales may affect Hawke's Bay from Sunday night through to Monday morning.
People in Canterbury are advised to have contingency plans in place.
Christchurch Mayor Bob Parker is worried that the weather will make the earthquake damage worse.
Mr Parker told Morning Report he surveyed the destruction from the magnitude 7.1 earthquake from the air on Sunday aboard an RNZAF Iroquois.
Mr Parker said he is very worried about the weather and believes the strong winds could cause more damage.
He said he is scared also about the impact of the predicted cold weather on Monday.
He said the priority is making sure people are safe.