15/09/2015 7:34 AM AEST | Updated 15/07/2016 12:51 PM AEST

Malcolm Turnbull, Australia's New Prime Minister, Optimistic As Deputy Defends Knifing

Video edited by Tom Compagnoni

Prime Minister designate Malcolm Turnbull has declared his first morning in the top job as a "a great time to seize the day," as his deputy defended the decision to axe Tony Abbott.

The former Communications Minister made Tony Abbott the shortest serving prime minister since Harold Holt by a vote of 54 to 44, with one informal vote, in a Liberal party room ballot following a sudden spill on Monday.

Turnbull will be Australia’s sixth Prime Minister in eight years, dating back to John Howard.

"This is a great time to seize the day," Mr Turnbull told reporters in Canberra on Tuesday morning.

"I'm filled with optimism and we'll be setting out, in the weeks and months ahead, we'll be setting out more of those foundations which will ensure our prosperity in the years ahead.

"There has been a change of Prime Minister, but we are a very, very strong Government, very strong country, with a great potential, and we will realise that potential.

"This is a turn of events I did not expect, I have to tell you."

Foreign Minister Julie Bishop easily retained her role as deputy leader after a late challenge from veteran Defence Minister Kevin Andrews failed 70 to 30.

The foreign minister informed Mr Abbott he had lost her support following question time on Monday night.

Politics can be brutal. What can be lost in the rough and tumble is the people, and the relationships. I’ve known...

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Ms Bishop told Nine's Today show Monday's events were emotional but she denied she had been disloyal to Mr Abbott.

"He was calm. He was obviously very hurt," she said.

"Emotionally, this is a very draining time for people and I feel for Tony and I feel for Margie and his daughters. I knew them well, and I know what stresses and strains that the leadership are under.

"I think there were tears shed."

She said she was obligated to approach Mr Abbott with the party's views.

"I informed the leader of the views of the majority of the party room. That's the role of the party room. That's the role of the deputy. If I had not done that, I would have been seized of information that the leader needed to know," she said.

Ministerial changes are expected, particularly the crucial Treasury portfolio currently held by Joe Hockey.

There has been no word yet from Abbott, who last night addressed the party.

Defence Minister Kevin Andrews said he spoke to Abbott last night, and described his mood as "reflective".

"He said he believed we had been a good government in difficult circumstances," he said.

"He thanked people who supported him over the years," Andrews told the Nine Network on Tuesday.

"He said that he believed that we had been a good government in difficult circumstances. And I think there was a wide deal of respect for him."

Andrews said he ran as deputy leader to indicate he could work with Turnbull.

Nationals deputy Barnaby Joyce said he met with Turnbull on Tuesday morning.

“What Australia wants is good Government and good Government starts with strong Coalition agreement and I'm sure Warren (Truss) will be right up to the task there to make sure we get the best possible deal for regional Australia,” Joyce said.

“Let the Australian people decide on that.”

Small Business minister Bruce Billson said Abbott had pledged full support for the decision.

“He said he will give his full support now that the decision has been made and that's a mark of the quality and character of the individual,” Billson told the ABC.

“He made it clear he will support PM Turnbull. Whatever you might say about Tony Abbott, he is one classy, genuine individual.

“Very honourable man and he made it clear that he's disappointed with the result last night but he has given so much to the Liberal Party and the Liberal Party and our colleagues have afforded Tony Abbott so much as well.”

NSW Premier Mike Baird offered his condolences to his mate Abbott and paid tribute to his dedication to service.

"This desire to serve, mixed with a deep love of Australia, took him into politics, and ultimately to the highest elected office in the land," he said.

"Not once have I sensed it was due to a thirst for power. Rather, he has an unquenchable desire to give back. This has always been grounded in a deep humility."

Labor deputy leader Tanya Plibersek said the the change of leadership would not mean a change of policy.

"Malcolm Turnbull has supported cuts to education, in his case cuts to the ABC," she said.

"What we've seen is a change of salesperson, not a change of product.

She said she expected there to be a "sugar -hit" of popularity for Mr Turnbull.

She predicted people would come to read his confidence as arrogance.