Governor-General Quentin Bryce, the Queen's Australian representative, said while delivering the final Boyer Lecture of the year in Sydney she hoped the nation would evolve into a country where "people are free to love and marry whom they choose".
"And where perhaps, my friends, one day, one young girl or boy may even grow up to be our nation's first head of state," she said in the lecture on Friday night.
Mr Abbott, a staunch Catholic and monarchist who doesn't support gay marriage, said "it's more than appropriate for the governor-general approaching the end of her term to express a personal view."
"And as you'd expect of Quentin Bryce, she did it in graceful style," he told reporters.
When asked whether Ms Bryce's comments had swayed his view, Mr Abbott offered a vague answer.
"Different people have different views on these subjects. She was expressing her view, others express their views."
The Chair of the Australian Republican Movement, Geoff Gallop, welcomed the comments, saying an Australian head of state would send a powerful message.
"We will always be friends with Britain, but now we should be equals," Gallop said.
"We need an unambiguous, independent national identity that reflects and celebrates our freedom, our unity, our values of the fair go and our place in the world."
GOVERNOR-GENERAL'S COMMENTS 'CROSS THE LINE': MONARCHISTS
But monarchists have criticised the comments. Liberal Senator Dean Smith says Ms Bryce has crossed the line by becoming involved in the political debate on two sensitive issues while still acting as Governor-General.
"Last night's departure into current political events will come as a slap in the face to many, many Australians, and a significant breach of trust because she would know better than most that that central office is so integral to stay above the day to day political fray," he told the ABC.
"She has stepped across the line in inviting a commentary around two very, very sensitive issues."
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David Flint, national convenor of Australians for Constitutional Monarchy, says the Governor-General's comments are "a great pity".
"The constitutional system requires that the Crown be above politics so that when the representative of the Crown... speaks, they shouldn't be talking about politics," he told the ABC.
"It's just, it goes against the position. There are a number of people who are now going to wonder about her. There's this sense of division that she's created and the position is not intended to be divisive -- it's intended to unite and be above politics.
"So we've got commentators everywhere on these issues, couldn't she have left them alone until she was out of the office?"
Australians voted against becoming a republic in a 1999 referendum and over the years the issue has faded into the background.
Australia is a parliamentary democracy that retains Britain's monarch as its head of state. Other former British colonies such as Canada and New Zealand have similar constitutional systems.
Australians voted against becoming a republic in a 1999 referendum and over the years the issue has faded into the background.
