The Canadian government, in sweeping proposals to comply with a new constitutional Charter of Rights, has said that it intends to remove barriers preventing homosexuals from serving in the Royal Canadian Mounted Police and other services, abolish mandatory retirement for federal civil servants and seek to broaden the role of women in the military.

Given the large parliamentary majority held by the Conservative government of Prime Minister Brian Mulroney and the longstanding tradition of party discipline, approval of the series of changes that Attorney General John C. Crosbie detailed before Parliament yesterday normally would be a routine matter.

However, several members of Mulroney's party indicated that they were strongly opposed to some of the proposed changes, particularly the one prohibiting discrimination on the basis of sexual orientation in all areas of federal jurisdiction. They indicated they would press to be released from their commitment to support government legislation.

The stern-faced, scarlet-coated mounted police, in many ways the symbol of Canada's devotion to peace, order and good government, long has followed an unwritten policy of barring homosexuals, according to observers here.

"We are condoning a third sex, somebody who is not exactly normal," Conservative Party member Alex Kindy told reporters. "We are sending out a dangerous message."

An existing Canadian armed forces administrative order effectively bans recruitment of homosexuals and allows for the dismissal of those on the force. Last year, a parliamentary subcommittee reported that 44 members of the Canadian armed forces were dismissed under provisions of the order in 1983 and 38 more in 1984.

The U.S. military does not allow homosexuals to enlist, and homosexuality is cause for discharge from the services.

There is no mandatory retirement age for U.S. federal government workers.

The pending reforms that Crosbie outlined in the House of Commons put the government on record as being committed to equal treatment of women in the military so long as this was compatible with the need to be "operationally effective in the interests of national security."

"The government believes that one's sexual orientation is irrelevant to whether one can perform a job or use a service or facility," a report on the proposed changes introduced by Crosbie said. "Sexual orientation is not a ground for denial of a security clearance. Rather, the criteria applied are loyalty to Canada and reliability."

Crosbie ducked repeated questions by reporters in Ottawa on whether the changes mean women would be permitted to perform combat duties. He was vague about what precise steps he intends to take as the reforms are phased in over the next year. He also indicated that he knew that some of the proposed amendments to laws or substitutions for administration regulations that would be necessary to carry them out will be controversial and opposed by members of his own party.

"Equality and social justice require that individuals be given a fair chance to make their own way in society and that when opportunities are not fairly distributed, positive action be taken to ensure that they are," he said. "This includes eliminating systemic discrimination."

Although the notion of individual rights has been entrenched in the U.S. Constitution virtually since the beginning of the republic, it is a relatively new idea here and has evolved in the period since World War II as Canada consolidated its independence from Britain.

It was not until 1982 that then-prime minister Pierre Trudeau won approval for the Charter of Rights, which resembles the Bill of Rights in the U.S. Constitution but with substantial differences.

Trudeau had begun to act in the late 1960s in order to strengthen citizens' loyalty to Canada, as opposed to their home provinces. It was a time of aggressive provincialism in Canada, particularly in French-speaking Quebec, which considered seceding.

The changes that Crosbie outlined yesterday are part of the ongoing efforts of governments and courts here to implement the new charter.

Other targets Crosbie announced include:

*Making all federal buildings accessible to people in wheelchairs by 1995.

*Efforts to "reasonably accommodate" persons whose days of religious osbservance do not fall on Sundays or other statutory holidays by allowing them to to take alternate days off.

*An agreement in principle that the mentally disabled should be allowed to vote in federal elections.