Anti-monarchy group, Republic, said the Prince of Wales' publicity team was having to work tirelessly to change public perception after his regular controversial statements on political topics.
A spokesman said: "The royal PR machine is facing a crisis as Charles prepares to take the throne.
"Charles has routinely abused his position of power, privately lobbying Cabinet ministers and influencing Government policy with his own political agenda.
"It's unsurprising that royals are rushing to change Charles' public image as he prepares to become king, but does he really expect us to believe he won't capitalise on all the powers he's about to inherit?
"King Charles is just around the corner and we should be having a wide-ranging national debate about our country's future, not a coronation by default."
Speaking on BBC documentary Prince, Son and Heir, Charles at 70, Prince Charles said: "If it's meddling to worry about the inner cities as I did 40 years ago, then if that's meddling I'm proud of it.
“I think it’s vital to remember there’s only room for one sovereign at a time, not two.
“So, you can't be the same as the sovereign if you're the Prince of Wales or the heir.
"But the idea, somehow, that I'm going to go on in exactly the same way, if I have to succeed, is complete nonsense because the two - the two situations - are completely different."
