The sessions were scheduled because the draft water resource plan for the Namoi catchment is on public exhibition. The closing date for feedback is October 29.
A message on the Department of Industry's website said the sessions for Gunnedah and Wee Waa had been "postponed" and the page would be updated "when more information is available".
The consultation session at Tamworth will still go ahead on Wednesday at the Best Western Sanctuary Inn from 1.30pm.
The department is yet to reveal the reasons for cancelling the event. The NVI contacted organisers for comment but did not respond by late on Tuesday.