Hastings District Council will hold an extraordinary meeting later this week over a leaked proposal for a water museum in the centre of the city.
Mayor Sandra Hazlehurst confirmed the meeting on Monday afternoon, saying it was to discuss the "breach of confidentiality through the release of public excluded information".
The meeting will be held on Friday.
Hazlehurst said no investigation was underway into the leak at this stage. However, she said Friday's meeting will be held to "consider an investigation of the breach of confidentiality".
"This is a very serious matter. Our Council cannot run without honesty, trust and integrity."