But the final decision on whether Del Mastro will be permitted to return to the Chamber will be made by his Commons colleagues through a process that could begin as early as next week.
In an interview with Evan Solomon, host of CBC Radio's The House that will air Saturday morning, Del Mastro confirmed that he intends to stay on as an MP.
"My intention is to continue to work in my position, in my capacity as a member of Parliament for Peterborough," he told Solomon.
He also stated that he will appeal the decision, and claimed that Elections Canada had initially offered him a deal, which he refused.
""I could have taken a deal long before this case began," he told Solomon.
"It would have resulted into a small fine and no barring of our privileges or ability to run in future elections."
But he said he chose to fight the charges instead.
"I've always stood by the principle that you don't say that you did something that you didn't do."
Under the Criminal Code, any parliamentarian convicted of an indictable offence and sentenced to a jail term of two years or more automatically forfeits their seat. The charges on which Del Mastro was convicted carry a maximum sentence of one year each, which means that rule likely wouldn't apply in his case.
But the Elections Act states that anyone convicted of an offence deemed an "illegal practice"— which, as of Friday, Del Mastro has — is not entitled to be elected, or sit in the House of Commons for a period of five years from the date of conviction.
NDP call on speaker to 'clarify' next steps
On Friday, New Democrat House Leader Peter Julian asked the Speaker to clarify what steps should be taken by the House to comply with the law.
"The statutory provisions which render a member of Parliament ineligible to sit in the House of Commons are unambiguous," he noted.
"The Canada Elections Act … stipulates a person who has been found guilty of an illegal or corrupt practice cannot be elected to or sit and vote in the House of Commons."
In response to Julian's query to the chair, Conservative House Leader Peter Van Loan agreed that the question of whether a member should be allowed to keep his seat is, indeed, one that falls to the House, as a whole, to make.
But he pointed to a "lack of clarity" over the details decision itself — which, he suggested, was "based entirely on upon media reports and social media tweets, which have already been proven to be contradictory in a number of ways."
"For example, it is my understanding that two of the guilty findings were also stayed," Van Loan noted. "I do not understand what the implication of that is."
Given that confusion, he said, "it is very difficult for us to be able to make a decision at this point in time."
(In fact, just one of the charges was stayed — at the request of the Crown, as it was rendered moot when he was found guilty on another charge.)
'Primary documentation' needed, says acting speaker
Acting Speaker Barry Devolin agreed.
"At this point, the Chair has only heard second-hand media reports, in terms of what happened," he told the House.
"However, we will certainly get the primary documentation — and we will consider it, as important as it is, and we will get back to this House as quickly as possible, as it relates to this matter."
In a statement issued by his office on Friday afternoon, Van Loan concurred that Del Mastro's conviction "raises serious concerns."
Given that, he said, the government would like to see the question referred to the procedure and House affairs committee "to examine the matter, and determine what steps should be taken."
Outside the Chamber, Julian called the ruling "a fundamentally important issue."
"To my mind, this is a serious violation," he told reporters.
"He’s been found guilty. To my mind, there’s no doubt that he cannot continue to sit in the House of Commons."
Del Mastro "withheld and falsified information, ripped up the Elections Act, in terms of his own expenses," Julian continued.
"You can’t break these laws with impunity."
Liberal MP Wayne Easter told reporters that it seems "pretty clear" to him that Del Mastro will have to give up his seat.
"Once convicted of an offence, then you’re not allowed to sit as a member of Parliament," he noted.
"Up until the point of conviction, you operate under the presumption of innocence. Now .... even if it goes to appeal, you have been found guilty, so you’ve lost that presumption of innocence. So I expect even if there is an appeal that [Del Mastro] would have to step down as a sitting member of Parliament."