Milton homeowners say they are in the dark about council controls to reduce the town's flood risk.
The South Otago town is home to about 2000 people and has been flooded by the Tokomairiro River three times in the past six years.
Some 580 properties have received a letter warning them their properties are flood-prone and alerting them to a public meeting on Tuesday night.
The Clutha District Council and the Otago Regional Council will reveal a project called Milton 2060, drawn up in response to major flooding in 2006, 2007 and 2010.
But resident Lyn Smart says the letter she received gave no idea that such important changes are planned.
Mrs Smart says she is surprised her property is a risk, because it has not flooded once in 50 years.
The district council is planning to tag the properties on their Land Information reports and introduce new controls on any building works which could affect the properties around them.
Special permission will be needed to for housing extensions or new buildings on the land.
Clutha mayor Bryan Cadogan says the notices are likely to reduce the value of the properties and he wishes the council did not have to take the action.