Napier's mayor Bill Dalton has had a formal complaint laid against him with the Auditor-General in relation to a proposal to amalgamate Hawke's Bay's five councils.
Hastings deputy mayor Cynthia Bowers said she lodged the complaint after Mr Dalton suggested sponsors would stop supporting the Magpies rugby team because its assistant coach supported amalgamation.
Assistant coach Danny Lee posted a pro-amalgamation video on a Facebook page.
Mr Dalton commented on the page that Mr Lee's stance would prompt some sponsors to review their position.
The video was then removed, Ms Bowers said.
"That just reinforced to me that the stand that Mr Dalton had taken had had effect to the extent that Danny Lee no longer wanted his personal views to be expressed publicly."
Mr Dalton's comment amounted to a threat, and has stifled Mr Lee, she said.
Mr Dalton would not comment for now.