Lawyer, academic, women's activist and grandmother Quentin Bryce was sworn in as Australia's governor general Friday, the first woman to act as the British queen's representative Down Under.

Bryce, 65, is the only woman to take on the vice-regal position, which includes becoming the commander-in-chief of the armed forces, in its 107-year-history.

Her appointment was announced earlier this year after Queen Elizabeth II approved Prime Minister Kevin Rudd's recommendation that Bryce, then governor of Queensland state, take the post.

As she pledged her allegiance to the British monarch, Bryce said she would carry out her duties with "solemnity, impartiality, energy and a profound love for the country we share."

"I feel deeply the gravity of the role bestowed on me today," she said.

The appointment of Bryce, who grew up in a small outback Queensland town and went on to become a lawyer, academic, women's activist and sex discrimination commissioner, has been well received here despite an ongoing debate over whether Australia should become a republic.

Addressing the senate chamber after being sworn in by High Court Chief Justice Robert French, Bryce said that Australians were savvy participants in their democratic system and careful scrutineers of its performance and values.

"We are informed and not afraid to question," she said. "Equally, we embrace change as a natural and necessary consequence of our evolution.

"Our growing capacity to balance tradition with renewal is a sure and uplifting sign of our standing as a sophisticated and highly functional civilised society and member of the global community."

Bryce promised to "do my very best to observe, sustain and uphold the principles, convention and rule of law that are our foundation."

"I promise to be alive, open, responsive and faithful to the contemporary thinking and working of Australian society," she added.

"Australians, you have entrusted a great deal to me, I will honour your trust wholeheartedly."

Queen Elizabeth is formally queen of Australia despite the country's independence from Britain and the governor general acts as the monarch's representative in Australia.

Although they perform largely ceremonial roles, the governor general can appoint a prime minister in the event of a hung parliament after an election and has the power to dismiss the leader.

The governor general is nominally the commander-in-chief of the armed forces but in practice they act on the advice on the government.

Federal Sex Discrimination Commissioner Elizabeth Broderick said given women made up only 25 percent of the lower house of the Australian parliament and just 13 percent of the Federal Court bench, Bryce's appointment was historic.

"A female governor general sends a message we all need to hear -- especially now at the beginning of the 21st century when our nation's progress in achieving substantive gender equality has stalled," she said.

The prime minister, an avowed republican, also praised the fact that Australia had for the first time in its 107-year history of federation sworn in "a truly wonderful woman" as governor general.

"It took us 107 years but we got there in the end," he said.

Bryce succeeds Major General Michael Jeffery who retired this week.