The number of Senate vacancies is set to reach 24 after two senators announced their departures Tuesday.
A third senator announced her intent to sit as an Independent.
Conservative Senator Irving Gerstein, who is nearing the mandatory retirement age of 75, confirmed his retirement in a statement.
Gerstein has been head of the Conservative Fund of Canada, the Conservative Party's highly effective fundraising arm, for years and was appointed in 2009 by then-prime minister Stephen Harper.
In a farewell speech in the Senate, Gerstein referred to the Liberal government's plans to make appointments "non-partisan," saying it "just doesn't make sense."
"Colleagues, I came into the Senate as a bagman and I'm going out as a bagman and I'm very proud of that fact," he said to thunderous applause. "I continue to believe the job of raising the funds of the Conservative Party — or for that matter any party — is both necessary and honourable. Political parties require money to operate.
"Do we really want to exclude a large group of potential candidates for a Senate appointment just because they have previously engaged in Canada's democratic process and therefore have ties to one party or another?"
Gerstein's name was drawn into Senator Mike Duffy's fraud trial, when former Prime Minister's Office chief of staff Nigel Wright testified Gerstein had initially offered to repay Duffy's ineligible Senate expenses from the fund. Wright said the offer was withdrawn when Gerstein learned Duffy's expenses were much higher than thought.
Gerstein told a Conservative convention in 2013 he made it "absolutely clear" to Wright the fund would not pay the expenses "and it never did."
Chrétien-appointee to sit as Independent
Gerstein's announcement came after Senator Pierrette Ringuette, named to the upper chamber by Jean Chrétien, said she would leave the Senate's Liberal caucus and sit as an Independent for New Brunswick.
"Canadians have been clear in their desire for a non-partisan Senate. The status quo is not acceptable," Ringuette said in a statement.
"The Senate, as an institution, and senators themselves, should be working to remove partisanship from the chamber and with that goal in mind, I believe in taking the proactive approach and sitting as an Independent."
- Senator John Wallace quits Conservative caucus
- Jacques Demers leaves the Tories to sit as Independent
Ringuette was appointed in 2002 after serving as an MP for Madawaska-Victoria from 1993-97.
In early 2014, Liberal Leader Justin Trudeau expelled all senators from his Liberal caucus, insisting there was no longer any such thing as a Liberal senator.
Since then, most of the former party members have continued to work together as a caucus, still calling themselves Liberals in the Senate. This new caucus has no direct affiliation with the governing party, save that they were appointed by a previous Liberal prime minister.
In her statement, Ringuette said she has hope the Senate can fulfil the role of being an institution of sober second thought and in hopes of having that happen sooner, she was making her move.
"Effective change in the Senate will need to happen from within and I believe as more senators are appointed as Independents and more current senators move away from the hardline partisanship of the past, we will be able to make those changes," she said.
Two former Conservative senators, both appointed by former prime minister Stephen Harper, recently left their caucus to sit as Independents.
Former Montreal Canadiens coach and Quebec senator Jacques Demers left the Tory caucus in December.
New Brunswick Senator John Wallace resigned from the party caucus in November, citing irreconcilable differences between him and his caucus colleagues.
Manitoba's Chaput cites health
Also Tuesday, Maria Chaput, who was appointed to the Senate in 2002 by Chrétien, announced her resignation due to health reasons.
"It has been an honour and a privilege to sit in the Senate of Canada and to represent Manitoba, especially official language minority communities," said the francophone senator in a statement.
"My time and my role within this institution have been special for me and something for which I will always be grateful."