The Christchurch City Council has installed pumps around the city's flood-prone Flockton basin ahead of forecast wet weather.
Prolonged rain is expected throughout Christchurch and Banks Peninsula, starting on Sunday and continuing through to Tuesday.
Council staff and contractors have been working around the Flockton area on Saturday to install pumps ahead of the expected 75mm of rain.
The pumps aim to minimise the backflow of water from an area where the Flockton Drain and Dudley Creek meet, which has caused severe flooding to nearby houses at least three times this year.
Mayor Lianne Dalziel said even if the expected forecast did not arrive, it would be a good test of the council's flood prevention plans.
Council land drainage operations manager Mike Gillooly said it was the first time residents in the area had received help of this kind.
"We've deployed temporary pumps throughout the city before on numerous occasions but in this particular part of the network, I can't recall this actual operation being done," Mr Gillooly said.
"It's a temporary, short-term measure that we've been looking at as part of the taskforce. In fact, we were looking at it prior to that but we're just getting on with it.
However, the pumps would reduce the risk of flooding only in a low-level event, Mr Gillooly said.
"It's likely to have some benefit in the smaller storms. If we get a big storm (it will) probably not have as much benefit at all but anything we can do to reduce the depth and draw the water level down in the Flockton Basin is an improvement, so we're pulling out all the stops."
Residents in low-lying areas should take appropriate steps to protect their property, he said.
Heavy rain is also expected through much of the country during the next three days, including Northland, the Coromandel Peninsula, Nelson and Marlborough. In the Nelson ranges, 150-250mm is expected.
The wet weather is expected to arrive tonight and continue through Monday and Tuesday, and the Met Service is warning driving conditions could be hazardous.