A state of emergency has been declared for the entire Selwyn District.
Earlier the state of emergency was declared in the Springs Ward, including Lincoln, Tai Tapu and Prebbleton, after the Selwyn River overtopped its banks at a number of locations between Coes Ford and Lake Ellesmere.
Selwyn Civil Defence local controller Douglas Marshall says the extended state of emergency has been declared because of continuing and predicted flooding.
The Selwyn River had burst its banks on its northern side.
The extended declaration would cover issues on the southern side.
River levels were anticipated to continue rising due to persistent rain, and floodwaters joining the river from higher elevations, Marshall said.
Selwyn District Council staff were monitoring levels at the Halswell River, near Tai Tapu, and the Hawkins River, which is west of State Highway 1
Meanwhile, evacuations were continuing at settlements at the Upper and Lower Selwyn Huts, while other residents were self-evacuating.
There were about 120 huts in the settlements.
An evacuation centre was established at Lincoln Event Centre.
Reports of people rubber-necking in the area were of concern, Marshall said, adding people should stay of the area unless it was absolutely necessary.
Road conditions were extremely challenging, he said.