The federal government is facing pressure to create gender parity in Canada's upper chamber, two months after Prime Minister Justin Trudeau attracted global attention by forming a cabinet whose membership is half female.

A group of prominent women from across the country has seized on Mr. Trudeau's move to achieve gender equality in the cabinet and his promise of Senate reform, and is now calling on him to fill the 22 current vacancies in the Senate with women – which would create gender balance for the first time in the chamber's history.

In addition, the group – led by Donna Dasko, co-founder and former national chair of Equal Voice, a non-partisan organization advocating for women in politics – is asking that the female appointees be from diverse backgrounds, such as indigenous women and those from minority linguistic, racial and ethnic communities. This, they point out in a letter sent late last month to the Prime Minister, is in keeping with the Senate's mandate to represent minorities.

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"This is an historic opportunity," Ms. Dasko wrote in the letter that is signed by more than 80 women, including former Progressive Conservative prime minister Kim Campbell, former Liberal deputy prime minister Sheila Copps, actress Sonja Smits and Vancouver's deputy mayor, Andrea Reimer.

Currently there are 83 senators, 30 of which are women – representing 36 per cent of the Senate. Appointing 22 women immediately would make the chamber 50-per-cent female. The group says in the letter that "future appointees could include both men and women in equal numbers."

Paul Duchesne, a spokesman for Democratic Institutions Minister Maryam Monsef, told The Globe and Mail in an e-mail on Sunday that "we share the desire of the signatories to achieve gender balance in the Senate."

The Liberal government is in the process of establishing an Independent Advisory Board on Senate Appointments, which is to provide advice to the Prime Minister on Senate candidates, Mr. Duchesne explained. "The board will be guided by public, merit-based criteria, and nominees will be considered with a view to achieving gender balance in the Senate," he wrote.

The candidates are to bring a non-partisan "perspective" to the Senate, according to the criteria spelled out by the government. In addition, consideration is to be given to establishing gender balance and priority is to be given to "aboriginal peoples and linguistic, minority and ethnic communities."

The Prime Minister will be given a short list from which he'll choose the senators. It's hoped that five new senators will be appointed early this year, Mr. Duchesne said.

In the House of Commons, only 26 per cent of MPs are women – Canada is 48th in the world in terms of female representation, according to the group.

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"I think having more women and racially diverse women is going to change some of the outcomes of the studies and the witnesses we call," said Conservative Senator Nancy Ruth, a signatory to the letter who was appointed in 2005 by then-Liberal prime minister Paul Martin. Having more women on Senate committees, for example, creates more discipline and fairness, she said.

Ms. Ruth noted that Parliament is to deal soon with the issue of physician-assisted death after the Supreme Court of Canada struck down the law against it last February, finding it unconstitutional.

"If there ever was a woman's issue, that's it," she said. "We give them birth and we see them out because we statistically live longer. It's often the women in Canadian society who have to come up to these critical issues."

However, she said, she doesn't know how this move will play out. In 2008, then-prime minister Stephen Harper filled 18 Senate vacancies in one day. Ms. Ruth said she asked him to appoint women to all of those seats to achieve gender equality in the chamber, and he responded by saying, "Interesting." Of the 18 appointees, five were women.

Ms. Dasko believes her group's demands are the next "logical step" following the Prime Minister's decision to make half of his cabinet female.

"To me it's just natural. If we're going to have the principle in the cabinet, the Senate is an appointed body and it would be natural to do that," she said.

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She also believes that achieving gender equity in the Senate would help to make it more relevant to Canadians. If the Senate appears less partisan, it might be seen to be more credible, she argued.

The Senate has long been dismissed as a body of appointed partisans, and the perception is that some senators are lining their own pockets. For example, the trial of PEI Senator Mike Duffy on fraud charges has not helped the Senate's image.

Conservative Senator Linda Frum, meanwhile, is more interested in seeing if Mr. Trudeau fulfills his promise of a more independent and non-partisan Senate.

"That was the commitment he made, and that is the standard by which he should be judged, regardless of the sex, race, age or other attribute of his nominees," she wrote Sunday in an e-mail. "I congratulate every woman nominated, but what should most concern all Canadians about these Senate appointments is the integrity of Parliament and the truthfulness of our new Prime Minister. Dramatic gestures should not distract attention from broken promises."