High alpine lake levels will be pushed close to flood levels again this weekend and the MetService has issued a severe weather watch.
As much as 40 millimetres of rain is expected to fall in the headwaters of lakes Wakatipu, Wanaka and Hawea. The lakes are already high following heavy rain a week ago.
The Otago Regional Council has issued a flood advisory notice, but says the lakes should not reach flood alert stage as observed last week.
The Clutha River at the Roxbourgh Dam releases water at over 1000 cubic metres per second, but Contact Energy will begin reducing the flow from 6pm on Friday.
On Saturday, the dam will resume discharging water at that rate to match expected in-flows from the heavy rain.
Contact Energy is advising people living near the Clutha downstream from the dam to be aware that the river level will be changing without warning from Friday night for 24 hours.
West Coast warning
Heavy rain is forecast for Fiordland and trampers are warned to look out for rapidly rising rivers and slips.
MetService says about 80 millimetres could fall from midnight on Friday to midday on Saturday.
Heavy rain is also expected across southern Westland.