The chairman of NHS Highland is actively trying to persuade people to vote against Scottish independence.
Gary Coutts, who is paid £29,640 a year by the health service, is taking part in a hustings event at Dingwall Baptist Church on Monday.
He will be debate Dave Thompson, SNP MSP for Skye, Lochaber and Badenoch, who will be arguing the case for Scotland to go it alone.
Mr Coutts’s decision to campaign for a No vote on September 18 puts him directly at odds with Health Secretary Alex Neil, who is aware of the chairman’s stance.
The former councillor, who lives near Inverness, was recently appointed by SNP Children and Young People Minister Aileen Campbell to chair the Children’s Hearings Scotland board on a four-year contract worth nearly £75,000.
But Mr Coutts insists he is entitled to take part as a private individual even though he is paid handsomely by the public purse.
“Scottish Government ministers are well aware I am going to be taking part,” he added.
“There is absolutely nothing that should, or does prevent someone in my position from taking part in public discourse in one of the most important decisions facing the country.
“I am perfectly well aware of party politics and I have been in the job long enough to know where to draw the line.”
Mr Coutts said he asked the director general of NHS Scotland a year ago if he would be allowed to take part in referendum events.
Mr Coutts, who said he had already spoken at several meetings, pointed out that the leader of the Women for Independence group, Jeane Freeman, was the chairwoman of the national waiting times unit at the Golden Jubilee Hospital in Clydebank.
Mr Thompson, who has been a Highland MSP since 2007, said he personally had no problem with Mr Coutts taking part in referendum debates.
A spokeswoman for the Scottish Government said: “Guidance has been provided to public bodies concerning the conduct of members and staff in the run-up to the referendum.
“By acting in accordance with the requirements of the issued guidance, including declaration of interests and making clear when comments are being made in a personal capacity, NHS board members have no prohibition on being involved in political activity.”