As part of the wild weather hitting parts of Canterbury and Otago, the Department of Conservation has declared a Code Red status for the Young Valley and its catchment due to significant rain.
The call means public access to the valley is closed until further notice.
Waka Kotahi NZ Transport Agency has also closed the Haast Pass Rd because of falling trees, flooding and strong winds and, State Highway 94 to Milford Sound is also closed because of avalanche risk.
There is no other route to Haast from Otago.
The Young Valley Code Red was issued because the heavy rain may have had an effect on the stability of a landslip dam in the north branch of the river.
Otago Regional Council rainfall data reveals more than 100mm of rain has fallen at Albert Burn, and more than 84mm of rain has fallen at Makarora, in the past week.
The Mountain Safety Council avalanche advisory reports high avalanche risks throughout the Southern region, including at Wanaka and Queenstown.
The MetService has issued a heavy rain and wind warning for today and tomorrow in the Otago lakes headwaters.
The Young Valley Code Red will be reviewed this afternoon.
A 2km-long lake formed in the north branch of the valley in 2007, after a landslip created a 70m dam, holding back 23 million cubic metres of water.
The Young River is a remote tributory of the Makarora River and the dam and its outflow is monitored for the safety of people in the Makarora area.
There is also a possibility of sediment discharges into the river.
Waka Kotahi said conditions were likely to be particularly treacherous in some areas overnight and urged motorists to stay alert and up to date with notifications.
Gale force winds also closed Treble Cone Ski Area and Cardrona Alpine resort for the day, frustrating holiday-makers.
In Canterbury, the Civil Defence and Emergency Management Group activated its emergency co-ordination centre in response to the severe weather.
■ Trampers should call Wanaka DOC office (03) 443 7660 (027 432 5378 after hours); and refer to Niwa parks weather website.
