The Canadian leader wrapped up a four-day visit to Australia on Friday, departing Canberra after delivering addresses at Parliament House and the Lowy Institute in Sydney.
Political strategist Jack Milroy said Carney received a "rockstar welcome" from across the political spectrum, signalling his growing stature as a global figure following his widely praised speech at the World Economic Forum in January.
During his visit, Carney expanded on that message, arguing the postwar international order was breaking down and urging middle powers to co-operate in response to rising geopolitical competition.
"Middle powers have more power than many realise," he said at the Lowy Institute.
"Europe, Australia, Canada, Japan, South Korea: this coalition has a GDP larger than the United States, three times the trade flows of China (and) the largest research and development spend in the world."
It was now up to other nations such as Australia, Japan and South Korea to stand up against the US and China as tariffs and conflicts wore on, Mr Milroy said.
"If it's only driven by Carney, it won't work in the long term and I think he would be the first to say that," he said.
"It's going to depend a lot on what we see from these other middle powers in the next three to six months."
Mr Milroy said Mr Carney's middle-power approach could see Australia and Canada acting as conveners in different regions.
Australia, for example, could bring together partners in the Pacific and southeast Asia, while Canada might convene nations with cultural or linguistic ties in Europe or Francophone Africa, he said.
Prime Minister Anthony Albanese said he had been working on developing relations with other middle powers, while also not forgetting Australia's historic alliance with the United States.
"My invitation to the G7, prime minister Carney coming here even at what is a turbulent global time, is an indication of the priority that Canada places on this relationship," he said.
Mr Carney appeared to back down from his initial support of US-Israeli strikes on Iran, suggesting they had breached international law as the conflict escalated.
Both leaders called for a de-escalation in the conflict, but Mr Albanese added Australia wanted "objectives achieved" from the war, saying the possibility of Iran obtaining a nuclear weapon had to be removed.
The prime ministers also announced plans to boost joint investment in critical minerals, which are used in electric vehicle batteries, solar panels and sensitive defence technologies.
"Preventing other powers from gaining monopoly on rare earth extraction ... given the amount of rare earths that come from Australia and Canada is a really, really important piece to come out of this visit," Mr Milroy said.
