In a speech late on Thursday, Governor General Michael Jeffery said such changes to the United Nations charter were needed, if the world did not want superpowers to act unilaterally.
It was an unusual and potentially controversial foray into policy matters by Jeffery, who became Queen Elizabeth II's representative in Australia after his predecessor resigned in disgrace.
"It seems to me that if the world does not want a superpower of the day to take unilateral or multilateral action against threats that it perceives to be inimical to its national interest, then the UN must be given authority and the appropriate tools to ensure that human rights and dignity of the individual ... are maintained," Jeffery said.
Hill on Friday backed Jeffery's comments as a "useful contribution"
"I don't think you want to turn a governor-general into an invisible person," he said, adding that he supported such changes to the UN charter.
"The definitions of self-defence, for example, do need further consideration. Self-defence was defined in an era when there were long lead-in times -- basically the enemy came over the hill and you had time to respond.
"In this day and age of weapons of mass destruction, terrorists that you don't see and don't know, it's forcing countries in effect to redefine for themselves and I would like to see the UN as a whole taking up that challenge."
Prime Minister John Howard said, however, that he thought such changes were unlikely.
The position of governor general has been a sensitive one in Australia since 1975, when then governor general John Kerr dismissed the government of Gough Whitlam, a move regarded by some as unconstitutional.
Jeffery was appointed earlier this year after the resignation of his predecessor Peter Hollingworth over a child sex abuse scandal. Hollingworth, a former Anglican cleric, resigned in May amid widespread controversy over his failure to discipline pedophile priests when he was archbishop of Brisbane in the 1990s.
The scandal around Hollingworth revived demands among republicans that the office of governor general, a holdover from Australia's days as a British colony, be scrapped.