Canadian charities are demanding Environment Minister Peter Kent retract accusations that some charitable groups are "laundering" foreign funds in Canada.

Imagine Canada — an umbrella organization representing the charitable sector — penned an open letter to the minister Friday expressing "serious concern" over his repeated use of the word.

"Imagine Canada does not take a position on the specific policy debate that triggered your comments," writes Imagine's CEO, Marcel Lauzière."However, saying that charities are 'laundering' funds, a criminal activity, goes far beyond the specifics of any one policy file."

Kent first accused charities of laundering money for foreign foundations on the April 28 episode of the CBC Radio's The House. It was in response to a question about environmental charities' fears the government is trying to silence them by removing their charitable status.

"Some groups with charitable status have been going well beyond the CRA (Canada Revenue Agency) guidelines for what is acceptable practice as a charitable agency. And there has also been concern that some Canadian charitable agencies have been used to launder off-shore foreign funds," Kent told host Evan Solomon.

Kent repeated the accusation on Tuesday in an interview with Solomon on CBC News Network's Power & Politics program. He sought to clarify his comments for a CBC Radio News story on Thursday.

"Whether you call it money laundering or a financial shell game or three-card monty, it is inappropriate under those organizations' charitable status," Kent explained.

Another minister involved in the environmental file was asked if he suspected environmental charities of money laundering.

"No. I'm not suggesting a criminal intent at all," Natural Resources Minister Joe Oliver told Power & Politics in an interview airing Friday.

Imagine asked Kent to reconsider his statements or provide details of the allegations.

"If you have specific knowledge of improper or illegal activity by any individual organization, it is imperative that you provide details to the appropriate investigating authorities. If, however, you misspoke, we would encourage you to retract your comments publicly," the letter reads.