The federal government has launched an internal investigation to find the culprit who leaked details from Auditor General Sheila Fraser's report on the gun registry, which is due out on Tuesday.

Fraser said she is "very upset" by the leak, and has strong suspicions about who is behind the act, but wouldn't reveal who she suspected.

Opposition MPs pointed the finger straight at the Conservatives, saying the leak came from within.

NDP critic David Christopherson wants the internal probe to go further -- he said the RCMP should investigate the matter.

"If there's going to be an investigation into the government, it ought not be the government that investigates the government," Christopherson said.

"We want to bring in the RCMP."

News agencies began reporting details of a report on Thursday dealing with the federal gun registry.

The leaked audit information suggested the previous Liberal government hid the registry program's cost overruns from Parliament for years.

Conservative MP Jason Kenney says the Tories want to find out if the leak came from the government, and then take the appropriate action.

"An internal investigation has been launched to see if this information was leaked from a government source," Kenney told the House of Commons.

"We certainly hope that it wasn't, and if it was, anybody responsible will be held accountable because this is a government of accountability."

Kenney later said he didn't believe the leak is a criminal matter.

Fraser is to present her report to the Commons, outlining the findings from her latest probe of the registry, which is estimated to have cost taxpayers at least $1 billion to date.

Reports indicate she has found new evidence the Liberals hid the true price tag for a long time.

With files from The Canadian Press