Attention defeated Tory candidates in Manitoba: Are you interested in a Senate seat?

Prime Minister Stephen Harper now has five Senate seats to fill after a long-time Liberal Senator surprised colleagues, and her own party, Thursday by announcing she's retiring.

In a speech intended to be a reply to the Conservatives' legislative agenda, the Speech from the Throne, Sen. Sharon Carstairs, the former leader of the Liberal Party in Manitoba and a past Leader of the Liberals in the Senate, shocked everyone by announcing she intends to retire in less than two weeks just before the Senate returns to work.

"When I leave this place today, colleagues, it will be to mail a letter to the Governor General indicating my decision to retire from the Senate, effective at 11:59, Monday, October 17," Carstairs told the upper chamber Thursday afternoon.

"This means that this will be my last day in this chamber and my last speech. I have never particularly liked our system of tributes, so I have chosen this way, and I ask for you to respect that. Do not do tributes now or at any time in the future."

In her twenty-minute speech, Carstairs, a senator with a strong personality who has often butted heads with fellow Liberals and those across the aisle, urged her colleagues to look seriously at Senate reform but cautioned the Conservatives plans are ill thought-out.

"It is inappropriate in today's day and age that we should sit in the Senate for potentially up to 35 years or more," she told the chamber. "I urge us to look seriously at term limits. I could, as you know, remain until 2017. I have chosen not to do that."

"At the same time, I urge us to proceed with caution. I would be remiss not to speak in my closing remarks about how important this institution has been to me for the last 17 years and why I urge caution about any changes we make to it."

Carstairs talked about the changes she witnessed since first taking notice of the Senate in 1959, when her father Harold Connolly was sitting in the upper chamber.

Security, she suggested, had changed dramatically. "No one even intervened when I took my father's car and managed to drive it between two black Cadillacs and smashed into both of them," she told the upper house.

But the Manitoba senator mostly talked about her work on palliative care and the numerous reports the Senate had done on the issue of aging.

"No member of Parliament has the time to do this kind of work, and therefore we must be cautious to not turn this place into a mirror image of the place down the way," she said.

"Honourable senators, we do good work, but it is frequently not the same kind of work that they do in the other place. I urge caution. I believe there will be unintended consequences of the changes this government proposes, and I believe they will not be in the best interests of our great country. To have two chambers with identical mandates chosen in identical ways would be unworthy of our nation.

Honourable senators, I bid you farewell. Keep healthy and happy and continue to put your country ahead of politics. You make this place a special place and a country to be admired around the world."

There are currently four vacancies in the Senate: one in Newfoundland and Labrador, one in Quebec and two in Ontario.

There are none in New Brunswick, where Premier David Alward recently announced he plans to introduce legislation that would establish province-wide Senate elections.

Harper's associate director of communications Andrew MacDougall told HuffPost last month the prime minister plans to fill the seats.

"(There is) nothing to announce now. Appointments will be made in due course," he said in an email.