In a statement to the NVI, a department spokesperson said the decision was made because it was "a stressful time" for water users.
"Across NSW water users are under extreme pressure due to drought. We understand this is a stressful time for many of our stakeholders in the Namoi region and the department has decided to postpone consultation sessions on the Namoi Surface Water Resource Plan," they said.
"The department has contacted stakeholders directly to confirm consultation sessions in Wee Waa and Gunnedah have been postponed.
"The department is committed to returning to these communities as soon as possible to continue discussions about the plan."
The closing date for feedback on the plan was October 29 but the spokesperson said it would be extended.
"We want to give the community time to respond to the plan so the closing date for submitting feedback on the plan will also be changed once new consultation sessions are schedule," they said.
The session was earmarked for Wednesday morning in town but was canned by organisers. The Wee Waa session has also been postponed.
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.