Rain is forecast to continue to fall on the saturated South Island, bringing fears that more flooding will damage already sodden pasture lands.
Already heavy falls have caused flooding, closed roads and bridges and forced homes to be evacuated
MetService predicts a further 50-70mm of rain will fall by tomorrow morning.
Otago Regional Council duty flood manager Mike Goldsmith said it would be monitoring stream and river levels in Dunedin, Mosgiel and Outram over the next few days.
Rivers in North Otago were also higher than normal due to the persistent rainfall over the last few days and it was expected the Shag, Kakanui and Waianakarua Rivers would rise further today and tomorrow.
"As the ground has been heavily saturated from the sustained rainfall over the past few days, river flows can change quite quickly, and everyone needs to be vigilant and keep a close eye on river levels," Mr Goldsmith said.
Federated Farmers said the prolonged rain was a cause of concern during a very busy period in the farming calendar, with calving and in some pockets, lambing, underway.
"I know when we hit a long dry spell farmers will look back at the rain longingly. But what many need right now are days or weeks of fine settled weather to dry out," Federated Farmers adverse events spokeswoman Katie Milne said.
"The only way to describe much of rural New Zealand is sodden and there'll be plenty of people in the towns and cities who'd probably agree. Farmers are hoping for a decent fine spell in order for saturated pasture to recover."
Christchurch City Council said all roads closed yesterday were now open, however potholes were appearing on roads as the surface flooding eased.
A number of slips were being cleared by contractors this morning.
MetService last night issued a severe weather warning for Canterbury south of the Waimakariri River, with 40-60mm of rainfall expected from 8am today through to 6am tomorrow. The rain is forecast to be heaviest later today.
Banks Peninsula has been hit hardest by the latest downpours, with the tourist town of Akaroa receiving a massive 185mm over a 24 hour period, resulting in number of slips and trees coming down on to roads.
The eastern suburbs around the lower reaches of the Avon and Heathcote rivers and areas around the Lower Styx River burst their banks in parts and caused flooding.
Dudley Creek and St Albans Creek also overflowed and contractors were sand-bagging to protect some buildings.
Weatherwatch.co.nz forecaster Philip Duncan said late tomorrow night some more rain may return to the east coast north of Christchurch for a while as the main system cleared most of New Zealand.
But he said it would be "short lived and in less populated areas".