An Otago Daily Times reporter at the scene said an engineer, a flood prevention manager, contractors, the Wānaka Fire Brigade and a digger were on site working to control the water flow this morning.
The reporter said an engineer at the site said a controlled water release was the best of two bad scenarios.
Letting the pond burst would have created a "tidal wave'' of water that would have been even worse.
A steady stream of water was flowing downhill at 10.30am, the ODT reporter said.
- additional reporting by Regan Harris