A community has been isolated after a bridge started to collapse in Upper Hutt.

The Bridge Road bridge off Akatarawa Rd in Birchville has slumped in the middle, above a raging Hutt River.

It has been closed to traffic, leaving 80 houses cut off.

The bridge, which is on the verge of collapse, will be fully replaced, Upper Hutt Council spokesman Lachlan Wallach said.

He said residents can still come and go on foot, they’re hoping to have temporary vehicle access to the community through Totara Park soon.

The Bridge Road bridge off Akatarawa Rd in Birchville has slumped in the middle, above a raging Hutt River. Source: 1 NEWS

He believed the very high and very fast Upper Hutt river that runs below is partly responsible for the bridge’s failure.

Some 140mm of rain was recorded at Taungata in the Tararua Ranges between 1pm yesterday and 12pm today.

The community’s water main has ruptured but is expected to be repaired later tonight.

An Upper Hutt City Council spokesman said they're trying to find another way to access the area and to provide help to those in need. Source: 1 NEWS

The sewerage system is working, while the gas supply remains out.

If residents are concerned about their welfare, Mr Wallach said they should contact the Council.

The council has so far received around 20 requests for help, six of which were requests for sandbags.

Akatarawa Road has been closed because of a slip on the Upper Hutt City Council side.

Police said Beach Road, Te Horo, is flooded in two places and water flows across the road are very fast.