But first, the Montreal MP says Harper must be honest as to what he knew about the $90,000 cheque gifted to Senator Mike Duffy by Nigel Wright, Harper's former chief of staff.
"The issue is not Senate reform for now, the issue is the honesty of the prime minister, the issue is judgment, his ability to make sure that partisan politics will not affect the government of Canada," said Dion in an interview with CBC Radio One's Rick Cluff on The Early Edition.
"Again we're in the confusion between what you do for the party and what you do for the country as if the Conservatives were considering the government of Canada as their private property."
Dion said the next step after dealing with Harper's Senate scandal is not to abolish the Senate, as the official Opposition New Democrats have proposed, but to give it real powers to carry out its role as the House of Commons' 'sober second thought.'
"An elected Senate would be powerful," Dion said. "A Senate, when you have good people in it, well-chosen by the prime minister, may help the country."
'We need to know the truth'
Dion said a number of things would have to happen before the government could move forward with reforming the Senate.
First, it would need a ruling from the Supreme Court of Canada about how thoroughly the provinces must be consulted in a potential reform process. Harper began that process in February when he sent a list of six 'reference questions' to the court.
Then, according to Dion, the distribution of seats in the Senate would have to be changed to reflect the proportionality of each province's population. B.C. and Alberta currently have six Senate seats a piece, while significantly smaller provinces like Nova Scotia and New Brunswick have 10.
Additionally, Dion said rules would have to be in place to prevent an American-style deadlock between the two chambers on Parliament Hill.
But for now, Dion says it all comes down to the Senate expenses scandal that has entangled the government for the past few weeks.
"Mr. Harper appointed the wrong people at the Senate and at the end of the day we need to know the truth."
Harper was not in question period in the House of Commons on Friday to answer further questions from the opposition about the Senate scandal.
The Early Edition is on the air every weekday morning between 5:30 and 8:37 a.m. PT on CBC Radio One in Vancouver at 88.1 FM or 690 AM.