The online arguing has made Waitaki Mayor Gary Kircher "cringe", and prompted him to declare the spat was "hindering" the debate over the hospital's future.
Accusations of personal attacks and misinformation in public interactions between David Bruce and members of the Waitaki Community Hospital Action Group have been defended by both sides.
Over the past several weeks, Mr Bruce - secretary to the board of Waitaki District Health Services, which owns the hospital - has clashed with the group in heated online conversations about various issues related to the hospital.
Mr Bruce labelled it a "secret group" that had engaged in "constant attacks, misinformation, and in some cases lies" that were "not helping existing staff, or to attract new staff".
As he was a contractor, he was not bound by the company's strict social media policy, he claimed.
"I have responded to personal attacks on me," he said in an emailed response.
"I have emphasised from the start I act in a personal capacity as a resident of the district for more than 40 years."
Mr Bruce said he would soon step down from the role.
"I tendered my resignation as board secretary in April, to be considered as part of staff changes being made and because I wished to travel... A date is yet to be set because the company's focus is on more important actions."
Hospital action group chairwoman Dr Janice Clayton questioned why the company had not distanced itself from Mr Bruce's comments, which she said were "not appropriate".
"I prefer not to tit-for-tat with David or for others to do so because, for the most part, his comments are mischievous and not factual," she said.
WDHS chairman Chris Swann said he was not aware of the exchanges until contacted by the Otago Daily Times.
"I have to say I don't follow social media, and I purposely don't follow it. I haven't seen it, so I can't comment on it."
Mr Kircher said the conversations about the hospital and the company had got to the stage that they were "hindering" the company's activities.
"I just cringe at so many of the comments that are coming from a number of people on the hospital issue. It's a problem when there's rumours and allegations and not facts being stated. When it starts getting personal, it obviously isn't helping anyone."