A small community in Upper Hutt has been cut off by road after their access bridge slumped.
The one-lane bridge crossing the Hutt River at Birchville was closed this morning after it was seen to be slumping in the middle.
There are around 70 houses on Bridge Road, off Akatarawa Road, on the western side of the river, the Upper Hutt City Council says.
Water and gas was cut off but sewage was being discharged into the river. Residents were advised not to use river water because of the sewage discharge.
Engineers were looking at the bridge to determine how badly damaged it was and to look at safe alternative access.
"It is likely the high river level and its reasonable flow have attributed to the collapse," spokesman Matt Weavers said in a statement.
The council says residents caught on Bridge Rd should stay home and check their emergency supplies, especially water.
Those who couldn't get to their homes were urged to find alternative accommodation.
"It is important that people do not attempt to cross the river at any stage," the council said.
The council also says a large slip 3km north of farm park Staglands has closed the Akatarawa Road.
While the bridge was closed, there was still four-wheel drive access along the riverside, a police spokesman said.
It has been raining around Wellington but not heavily. The MetService has issued a heavy rain warning for the Tararua Ranges, north of Wellington, and people are being warned rivers and streams could rise.
In Lower Hutt two riverside carparks were closed because of flooding.
On the Kapiti Coast there was surface flooding and a slip had closed the Otaki Gorge Road to all vehicles except utes, the Kapiti Coast District Council says.