A main Christchurch river has burst its banks after a night of heavy rain.
The Heathcote River has overflowed, and is causing flooding in nearby areas.
Newstalk ZB's Chris Lynch says the water is overflowing onto roads and lapping at people's driveways although it hasn't reached any houses yet.
He said traffic in Christchurch is eerily quiet, and the NZ Transport Agency is telling motorists to avoid driving in Christchurch this morning unless they have to.
Cyclone Cook is now off to the east coast of the South Island and heading south. Much of the South Island is now under severe weather watches.