Scott Morrison declared he was the first Australian leader to be invited to the G7.

Key points: Scott Morrison and Boris Johnson discussed a post-Brexit trade deal on the sidelines of the G7 summit

Scott Morrison and Boris Johnson discussed a post-Brexit trade deal on the sidelines of the G7 summit The Australian PM expects a deal can be completed within a year of Brexit

The Australian PM expects a deal can be completed within a year of Brexit The two leaders also discussed forging closer ties on space matters after this year announcing the Australian Space Agency

Technically, that's true but former prime minister Kevin Rudd also cruised the halls of the G8 in Japan in 2008.

It's the same summit really, just Russia's been booted out.

Just as with Mr Rudd, Mr Morrison was not at the big table, but he brushed shoulders with leaders of the biggest economies in the world.

A meeting with British Prime Minister Boris Johnson, a warm encounter with French President Emmanuel Macron, a so-called "pull-aside" with US President Donald Trump that lasted as long as some bilateral meetings.

"I'm not one that rushes to the plane to attend summits," the Prime Minister declared to the Australian press who had travelled to the French seaside city of Biarritz to cover his visit.

"As Australia's Prime Minister, I always prefer to be in Australia dealing with issues on the ground domestically."

Although, his conclusion was that the summit was "necessary" and it was good he'd gone.

On the final day, Mr Morrison had the chance to sit down with Britain's new leader. Both had marvelled at their swimming adventures during the two-day summit at the picturesque seaside city.

Mr Morrison discussed the unrest in Hong Kong with Mr Johnson. ( Reuters: Neil Hall )

They'd discussed the cricket, briefly, agreeing the Ashes were not over yet.

"Well we've got two to go, we're not taking anything for granted," Mr Johnson gratuitously acknowledged.

But it was free trade that was more pressing.

With Brexit, which Mr Johnson has promised to deliver come what may on October 31, nations like Australia can sign off on trade deals, formally prohibited by Europe.

Boris Johnson has played down the likelihood of a securing a US trade deal with Donald Trump within a year. ( AP: Erin Schaff, The New York Times, pool )

The United States wants one but Mr Johnson has said that deal can't be done within in a year.

But Mr Morrison said Australia's is "match fit" to get one done in even less time.

"I'd like to think we can move quicker than that," he said.

"You've got to get around the table and work it through."

On Brexit, Mr Morrison thinks his newly appointed British counterpart can do what he's promised.

"I tell you, I sat in that room with him this morning you would be absolutely convinced of it, you would be pretty certain of it," he said with a laugh.

"We are going to have a great relationship despite his cricket sledging, which was very modest, I have to say."

Australia was an observer nation at the G7 summit, which comprises France, the UK, Italy, Germany, the US, Canada and Japan. ( AP: Andrew Harnik )

Nations keen to work with Australia in space

The French President invited Australia to be an observer at the elite grouping, which comprises France, the UK, Italy, Germany, the US, Canada and Japan.

"People are noticing what Australia is doing and they want us to be part of what's happening at this level," Mr Morrison said.

"I was particularly pleased that Australia's actions on establishing the national space agency … in Adelaide has actually been noticed and I'm thrilled about that."

The space agency came up during meetings with Mr Johnson and outgoing Italian Prime Minister Giuseppe Conte, who both indicated their countries were keen to team up with Australia on space matters.

The G7 leaders used their brief post-summit joint statement to reaffirm the existence and importance of the Sino-British Joint Declaration of 1984 on Hong Kong and call for violence to be avoided.

Mr Morrison discussed the unrest in Hong Kong with Mr Johnson and Canadian leader Justin Trudeau.

All three countries have a significant number of expatriates living in Hong Kong.

"I think the key is all of us working together to seek to de-escalate the situation and where we have opportunities to do that, then we will take those opportunities," Mr Morrison said.

"We're watching this very close and we're swapping notes."

ABC/AAP