Conservative MP Dean Del Mastro has quit the party's caucus after he and a campaign staffer were charged with intentionally breaking campaign rules during the 2008 federal election, he said in a statement Thursday.

Elections Canada alleges Del Mastro, who represents the Ontario riding of Peterborough in the House of Commons, intentionally overspent his 2008 campaign limit and tried to cover it up by reporting a $21,000 expense as $1,575.

It also alleges he contributed too much money to his campaign – $21,000, nearly $19,000 over the individual candidate contribution limit.

Del Mastro said he still intends to support the government's economic agenda, but has told caucus leadership that he is stepping out until the matter is resolved.

"Today I learned that Elections Canada laid charges against me pertaining to the 2008 General Election. As I have consistently stated in the past, I entirely reject these allegations and look forward to the opportunity to defend myself in court," Del Mastro said in the statement.

Del Mastro's first court date is set for Nov. 7 in Peterborough, said a spokeswoman for the Director of Public Prosecutions, which handles the prosecution of charges under the Elections Act.

Del Mastro and Richard McCarthy are charged with:

Incurring election expenses in an amount more than the election expenses limit.

Providing the chief electoral officer an electoral campaign return that omitted to report a contribution of $21,000, omitted to report an election expense of $21,000 and instead reported an election expense of $1,575, and in so doing provided information that each knew or ought reasonably to have known was false or misleading.

Providing to the chief electoral officer an electoral campaign return that omitted to report a contribution of $21,000, omitted to report an election expense of $21,000 and instead reported an election expense of $1,575, and in so doing knowingly provided a document that did not substantially set out the information required.

Del Mastro faces a separate charge of wilfully exceeding the contribution limit for a candidate in his own election campaign.

Maximum penalty 5 years in prison

McCarthy was Del Mastro's official agent, the campaign volunteer who handles the spending and reporting to Elections Canada. Candidates sign off on the documents sent to Elections Canada.

The maximum penalty for each charge is five years in prison and a $5,000 fine. The Crown can choose to to pursue a more serious indictable offence or a less serious summary offence. The penalty for the summary offence is a maximum of two years in jail and a $2,000 fine.

NDP House Leader Nathan Cullen accused the Conservatives of a pattern of bad behaviour when it comes to elections, pointing to senators who had the Senate pay their expenses while they were campaigning for the party, allegations of misleading robocalls and the so-called "in and out" scandal that saw money transferred from local Conservative campaigns for national ads during the 2006 campaign.

"We need fair rules that everybody follows, not two sets of rules — one for everybody else and one for Conservatives," Cullen said.

"The fact is that there are Conservatives sitting in that House of Commons that don't deserve to be there, that gamed the system."

Cullen had demanded that Prime Minister Stephen Harper kick Del Mastro out of caucus.

Del Mastro had been Harper's parliamentary secretary until the prime minister shuffled those roles earlier this month. Del Mastro was demoted to supporting the ministers managing the regional economic development agencies.

2-year investigation

Elections Canada has been investigating Del Mastro since April 2011, according to court documents released last year.

Investigator Thomas Ritchie alleges Del Mastro's campaign hired consulting firm Holinshed to provide $21,000 in voter identification and voter contact services during the election campaign held in the fall of 2008, and that Del Mastro wrote a personal cheque to cover the cost of the services.

Candidates are allowed to contribute a maximum of $2,100 to their campaigns.

Del Mastro's campaign reported a $1,575 cost for Holinshed's services.

Ritchie said in court documents that he believes Del Mastro knew he'd spent too much and tried to cover it up. The documents show Del Mastro paid Holinshed $21,000 from his personal chequing account. Del Mastro says that cheque was for services provided outside of the election period.

Ritchie also said in court filings that he believes McCarthy knew Del Mastro spent too much but submitted an erroneous election claim anyway.

'I've been patient'

Last June, Del Mastro told Evan Solomon, host of CBC News Network's Power & Politics, that the investigation was over.

"I've been patient because I've been waiting for Elections Canada to go through the evidence that I've provided," he told Solomon.

MP Dean Del Mastro (Adrian Wyld/Canadian Press)

"Some months ago they indicated to us that they had completed the investigation and yet still here we are, with no word from Elections Canada."

One of the key documents in the investigation was a memo, apparently written on Holinshed letterhead, by McCarthy. The memo noted the return of the $10,000 cheque and Ritchie said in court documents that he believed it was a false memo.

Del Mastro said that memo was a cheque stub that McCarthy wrote on.

"It's simply a note that we received a cheque from Holinshed on this date," he said.

Del Mastro also rose in the House on a point of privilege about the investigation, arguing it had dragged on too long. He also lashed out at Frank Hall, the president of Holinshed, prompting Hall to write a letter of complaint to House Speaker Andrew Scheer. Holinshed is no longer in operation.

Del Mastro teared up as he talked about the effect of the investigation on his family.

"Mr. Speaker, I feel violated and betrayed," he said.

"I feel strongly that this process has been conducted with malice and contempt for me as a member for and my family's well-being."

'Never incurred a $21,000 expenditure'

Del Mastro maintains he was reimbursed for election expenses and that he didn't exceed his limit.

"The campaign never incurred a $21,000 expenditure from Holinshed research. Did not," Del Mastro told CBC News last year.

"As I've indicated, the campaign did hire Mr. [Frank] Hall and his company and was invoiced $1,500 [$1,575 with GST] for a limited amount of work they did during the campaign. That is reflected in our campaign [records] and I was refunded for that."

The campaign issued two cheques to Holinshed in September 2008, to cover the $21,000 fee, one for $10,000 and one for $11,000. An analysis by CBC News, based on the court documents and Elections Canada records, shows McCarthy contacted Elections Canada to ask what the campaign's spending limit was.

Four days later, he cancelled the cheque for $11,000. Holinshed reimbursed the $10,000 cheque, but owner Frank Hall says he received a personal cheque from Del Mastro on Oct. 10, 2008.