Wanaka businesses have been asked by the district council to consider closing ahead of a sewer system shutdown at 4pm today.
Ardmore Street has already been closed due to flooding, the Queenstown Lakes District Council said.
The sewer system is being shut down to ensure sewage does not enter the lake.
It comes as both Lake Wanaka and Lake Wakatipu hit above the high lake-level threshold, with emergency teams on standby to help should levels get higher.
Wanaka CBD's 30km/h speed limit remains in place.