Prime Minister Stephen Harper's office has asked the RCMP to investigate conflict of interest allegations against one of his former senior aides.

The Prime Minister's Office on Wednesday also informed the conflict of interest office, the ethics commissioner and the lobbying commissioner about the allegations against Bruce Carson, Harper spokesman Dimitri Soudas said in an email.

The agencies were notified after the PMO learned about the allegations from the Aboriginal Peoples Television Network.

Meanwhile, Carson, who became executive director of the University of Calgary's Canada School of Energy and Environment after leaving his government position in 2009, issued a statement Wednesday night saying he is taking a leave of absence until the RCMP probe is completed.

Soudas said the ethics commissioner had signed off on Carson's position with the university when he left the PMO.

The allegations against Carson stem from APTN's discovery during a news investigation that Carson was apparently lobbying Indian and Northern Affairs Canada and the minister's office on behalf of an Ottawa-based water company that was trying to sell water filtration systems to reserves with water quality problems, APTN reported on its website.

The network said it has a copy of an email sent by Carson to the company in which he claimed advance knowledge about John Duncan's appointment as Indian affairs minister.

Carson, who is not registered as a lobbyist, later denied that claim in a videotaped interview with APTN.

"The prime minister has never met with, been spoken to or been lobbied by Bruce Carson on any of these matters," Soudas wrote in the email.

'Laws are clear and they must be respected'

Soudas did not explain exactly what "matters" he was referring to, although he did mention a five-year ban on lobbying by former political staff.

"The laws are clear and they must be respected. Those who do not respect them must and should face the full force of the law as well as the consequences that come with it," Soudas said.

"Given what we've learned about Bruce Carson, our government will not be in communication with him on any matter."

In his statement, Carson explained why he is stepping aside from his Calgary position.

"Out of respect for this process, the Office of the Prime Minister, and the many business and community leaders with whom I work, I will be taking a leave of absence effective immediately from all of my professional responsibilities until the investigation is concluded," it said.

Carson said he could not make any further comments, and indicated he had retained a lawyer.

CBC News was unable to reach him Wednesday.

Meanwhile, NDP energy critic Pat Martin criticized the PMO for waiting so long to investigate Carson.

"The PMO is trying to get out in front of a scandal the likes of which we haven't seen in a long, long time," said Martin. "Throwing Carson under the bus is going to be too little too late."

With files from The Canadian Press