Contractors are building emergency stopbanks beside the Avon River, in Christchurch, after flooding this week in the Avon Loop area.
Parts of Avonside Drive were flooded at high tide on Monday night, after several days of heavy rain.
Residents say the land next to the river slumped by 30cm in the earthquake on 22 February and the river bed is now higher.
They say the water flowed across lawns, up steps and backed up into household pipes, reaching levels not seen in the suburb since a flood in the 1990s.
The water receded with the tide, without entering any homes.
Civil Defence says contractors are working night and day to build the temporary stopbank.