OTTAWA -- Allegations of RCMP wrongdoing related to the illegal destruction of long run registry records are under investigation by the Ontario Provincial Police.

It's the latest twist in an unprecedented battle between the Conservative government and an independent officer of parliament whose job is to safeguard Canadians' access to government records.

Information commissioner Suzanne Legault issued a special report last week revealing she'd recommended in March that charges be laid against the RCMP for the destruction of long-gun registry records that were part of an active investigation.

The Harper government responded by retroactively rewriting the law, backdating the changes and burying the amendment in an omnibus budget bill it introduced earlier this month.

Legault calls that a "perilous precedent" that could be used by governments to retroactively rewrite laws on everything from spending scandals to electoral fraud.

While the Conservatives press ahead with an omnibus bill that will retroactively erase the offence from the books, Justice Minister Peter MacKay's office has confirmed that it sent Legault's findings to the Public Prosecution Service of Canada last week, which in turn handed the file over to an investigative agency.

"It will be looked at by a senior investigator," Sgt. Peter Leon of the OPP said late Tuesday, confirming an investigation will take place.

That doesn't mean charges will necessarily be laid.

"The Attorney General of Canada is not responsible for laying charges," MacKay's spokeswoman Clarissa Lamb said in an email Tuesday.

The public prosecutor's office would only say that it has passed on the file. "We don't direct an investigation," said spokesman Dan Brien.

Prime Minister Stephen Harper has said the Mounties were just respecting the will of Parliament when they destroyed gun records that were subject to an active access-to-information request and investigation by the information commissioner.

However the events in question took place before a Conservative bill to end the now-defunct, long-gun registry had been passed by the House of Commons in April 2012. To cover the RCMP's tracks, the government's most recent budget bill exempts all long gun registry records from the Access to Information Act, as well as any investigations, complaints or judicial proceedings related to those records -- and backdates the changes to October 2011, when the bill to end the long gun registry was first introduced in Parliament.

That's cause for a parliamentary investigation, the official Opposition NDP said Tuesday and they're requesting that the Commons ethics committee study the matter.

"It doesn't matter what party you're in, the issue of being able to retroactively change laws to protect a government agency or department that was involved in illegally shredding documents would set a very, very dangerous precedent for future governments," New Democrat Charlie Angus, a member of the committee on access to information, privacy and ethics, said in an interview.

"This is staggering on a number of levels."

The NDP motion for the ethics committee requests that the Justice Department produce "all of its documents relating to this case" and that MacKay, Public Safety Minister Steven Blaney and RCMP Commissioner Bob Paulson, among others, be called to testify.

A spokesman for Blaney would not say whether the minister would agree to attend committee hearings on what he called a "technical amendment."

"We firmly reject any claim that the RCMP did anything wrong," spokesman Jeremy Laurin said in an email.

Patricia Davidson, the Conservative vice-chair of the ethics committee, was not immediately available for comment. However Scott Simms, the committee's Liberal vice-chair, said it has just completed a study on identity theft and has an opening to take on new business, although time is tight.

The Commons is set to rise for the summer recess by June 23 and won't likely return before Canadians go to the polls to elect a new government in October.

The NDP's Angus says what's at stake is the power of government to effectively neuter independent parliamentary watchdogs while giving itself the power to rewrite history to negate criminal charges.

"This isn't inside-the-bubble bickering," said Angus. "These are the institutions that are supposed to have the power to ensure that parliamentarians and government remain honest."