Labour party leader Kevin Rudd, who swept to power nine days ago routing the coalition led by Conservative prime minister John Howard, was on Monday officially sworn in as Australia's 26th prime minister.
Rudd took the oath of office before Governor-General Michael Jeffrey in a brief ceremony in Canberra, while his deputy Julia Gillard, swore an affirmation, media reports said in Melbourne.
The ceremony was attended by Rudd's wife Therese Rein, and his children. Gillard's partner, Tim Mathieson and her sister Alison looked on.
The swearing of the two leaders is to be followed by the swearing in of the rest of the ministry.
Rudd will hold a full ministry meeting on Monday afternoon, as the government prepares for a vigorous start to its work.
The new prime minister wants to get preparation under way in the key areas of industrial relations and education before Christmas.
Interim legislation on industrial relations will be introduced as soon as the new Parliament commences in early February.
Later this week, the cabinet will meet in Rudd's hometown of Brisbane.
He has promised to take the cabinet regularly out of Canberra. Earlier, Prime Minister Rudd described it as just another day's work.
Rudd, who led Labour to its first federal electoral victory in 11-and-a-half years, on Monday said it was an important day. "Another day's work ahead," Rudd said when asked if he had butterflies.
"It's an important day for us because we turn a new page into the future. It's getting down to work on the agenda we put to the people during the election period. I'm really looking forward to that," Rudd said.
But he did acknowledge there was some personal excitement about today.
"Without a doubt, it's really important. You feel really good about it. I was having a chat with Therese over some Wheaties this morning and we're both feeling really chipper about it," he said, adding, "It's a good day."
Australia's stance on climate change remains on top of the new prime minister's agenda.
"As I said prior to the election, our first act as the incoming government would be to proceed with the ratification of Kyoto," Rudd said, adding "that remains our intention and when I land in Bali we would hope that ratification process would be under way."
But he warned a post-Kyoto agreement was not going to be easy. "It'll take a lot of time, a lot of horse trading, a lot of negotiation, it's going to be a tough process."
Another top priority for the new government -- industrial relations -- may take a little longer than ratifying Kyoto.
"The transitional bill will be prepared almost straight away, but we are not in a position to produce it of course until early next year when Parliament resumes," he said.
"We intend to proceed calmly, coolly and methodically in order to restore fairness and balance to the workplace," he said.
A second bill to deal with unfair dismissal laws is even further away.
"That will be prepared during the first half of 2008. The precise month we don't know yet because it's a complex drafting process as well," he added.