The North Wales police and crime commissioner has refused to apologise for describing voters who backed Brexit as "turkeys voting for Christmas".
The region's police and crime panel is set to uphold a complaint by a member of the public about the comments by Plaid Cymru's Arfon Jones on Twitter.
A report says he took an oath of office after his election promising to "treat others with dignity and respect".
Mr Jones denies that his comments were an issue of conduct.
Tweeting in reply to a Labour MP critical of Brexit, the former police inspector and Wrexham councillor said: "Ah well, told you so back in 2016. Leavers = turkeys voting for Christmas.
"It will get worse and much more expensive not to mention a double whammy for the economy and employment. Not seeing no benefits on the horizon."
The complainant felt offended by the nature of the language used by Mr Jones, describing it as "name calling".
A proposed decision report by the panel, which holds the commissioner to account on behalf of the voters, says Mr Jones should apologise since he describes himself as commissioner in his social media accounts.
"As the principles of the code of conduct should apply, then the comments made on social media were not appropriate and that the PCC had fallen short of his obligations taken as part of his oath of office, in that he agreed to treat others with dignity and respect," said the report, seen by the Local Democracy Reporting Service.
However, Stephen Hughes, chief executive of the commissioner's office, said Mr Jones stood by his views and his right to express them.
"Turkeys voting for Xmas is an English idiom where one clearly votes against one's economic interest," Mr Hughes said in an email to the panel.
"The use of a phrase to describe behaviours cannot possibly be a conduct issue."