Clutha District Council is strongly recommending that Tahakopa Valley Road, north-west of Tahakopa township, should only be used by light 4WD vehicles until further notice.

Manager District Assets Jules Witt said a combination of recent severe frosts, shading, and high volumes of heavy vehicle usage had left a stretch of about 12km of the gravel road, in the Catlins Forest Park, in a very soft and rutted condition.

"This has led to a rapid deterioration of the road surface to the point where it is now quite treacherous in many areas," he said.

Signs warning motorists are being erected at both ends of the road.

As any significant rehabilitation work would not be prudent until weather conditions improved, it was expected the signs could remain in place for up to three months.

Mr Witt said around half a dozen properties were located on the affected section of road.

"Council's first priority is to maintain access for the residents living along this road as they have no other alternatives," he said.

Council staff recently met with representatives of forestry interests in the area, and is working constructively with them to find alternative heavy traffic routes.