Monarchist group blasts the Governor General for commenting on King Charles's unpopularity

Canadian monarchists have sent a strongly worded letter to Gov. Gen. Mary Simon chastising the vice-regal for suggesting recently that there may need to be "conversations" about a future without the royals — and taking note of King Charles's unpopularity.

In a May 10 letter, Robert Finch, the dominion chairman of the Monarchist League of Canada, said it was "unbelievable" that Simon, the King's representative in Canada, would question the future of the institution and the likability of the sovereign on the eve of his coronation.

"Do you have any idea how much your remarks on the Canadian Crown and our King have deeply hurt many in the land to which you are supposed to bring unity and common purpose, rather than division and discord?" Finch said.

"How would you feel if your installation as Governor General had been clouded by someone on the government payroll whose comments would garner the attention that yours did?"

Finch also asked Simon to consider how Charles, "as a human being," might feel about seeing less-than-positive remarks in the press from someone hand-picked to be his eyes and ears on the ground in Canada.

In an interview with the Globe and Mail published last week, Simon said Canadians readily embraced Charles's mother, the late Queen Elizabeth. But she said the jury is still out on whether the new King can ever match her popularity, given his current polling numbers.

"While Canadians may never have felt great affection for Charles, they did embrace his mother right up until the end of her life, so I think King Charles needs to develop his relationship further with Canada," Simon said.

While stressing that now is not the time to discuss scrapping the Crown, Simon seemed to entertain the idea of a Canadian republic in the future.

"I think Canada first of all has to have a plan and an alternative as to what it is we want as a country," she said.

"It has to be a very big conversation about how we would do it and what kind of government we're looking for. And all those things take time, and sometimes they take years."

WATCH: King Charles's deep ties to Canada

Reached by phone Thursday, Finch said he's been "a big Mary Simon fan" and, under his leadership, the Monarchist League has a "track record of going out of our way to promote her work and defend her, quite frankly, when others weren't."

But he said Simon's pre-coronation comments were "disturbing" and raised the possibility that Simon might be a closet republican.

"Whenever a vice-regal talks about the structure of government we have, I just cringe. It's just not something that a vice-regal, in my view, should be talking about. It undermines her whole office and her whole authority," Finch told CBC News.