Albanese and China's Xi meet in Bali

Prime Minister Anthony Albanese has ended a six-year long freeze in Australia's diplomatic relations with China, meeting President Xi Jinping on the sidelines of the G20 summit.

During a half hour meeting in Bali on Tuesday afternoon, Mr Albanese and Mr Xi discussed China's trade sanctions on Australia, the detention of two Australians and Russia's invasion of Ukraine.

Mr Albanese said he and the president spoke honestly with each other and it was a positive meeting.

"It was not anticipated that in a meeting such as that you would get immediate declarations ... but it was very constructive," he told reporters.

"I've put forward (Australia's) position and I've used the language of moving forward together."

The prime minister said he spoke "firmly but politely" and urged Mr Xi to exercise China's influence over Russia and condemn the war.

In opening remarks ahead of the meeting, Mr Xi said the China-Australia relationship had run into some difficulties in the past few years.

"That was not what we were willing to see because China and Australia are both important countries in the Asia Pacific region," he said.

"We should improve, maintain and develop our relationship as it is consistent with the fundamental interests of both countries' people."

The president noted that since becoming prime minister, Mr Albanese said he would handle relations between the two countries "in a mature manner".

"I attach great importance to your opinion," Mr Xi said.

Malcolm Turnbull was the last Australian prime minister to have a formal meeting with Mr Xi in 2016.

Since then, increasing tensions over security arrangements and trade sanctions worth $20 billion have seen relations deteriorate.

But Mr Albanese, who set no preconditions for the formal talk, considered securing the meeting a success in itself.

He anticipated further meetings would take place in future and that both nations had taken an important step to moving forward.

Indonesian President Joko Widodo, hosting the G20 leaders, is keen for the two-day summit to deliver outcomes as the world grapples with rising inflation, climate change and the effects of the pandemic.

He called for unity and said collaboration was "badly needed" to save the world.

Earlier, Treasurer Jim Chalmers said while it was a welcome opportunity, it would not immediately fix the fractured relationship between the two countries or result in the removal of trade sanctions.

Dr Chalmers said the government remained deeply concerned over the detention of two Australians, including journalist Cheng Lei, who has been in custody for more than two years and denied contact with her family.

Liberal Senator Simon Birmingham welcomed the end of the Chinese government's ban on talks with Australia but urged Mr Albanese to protect Australia's interests.

"It was always counterproductive for China to refuse to sit down at the table with Australia," he told reporters in Sydney.

"Dialogue should be the last thing ended rather than the first thing."

On the first day of the summit, Mr Albanese chatted informally with Spanish Prime Minister Pedro Sanchez and German Chancellor Olaf Scholz.

He has also confirmed formal bilateral talks with British Prime Minister Rishi Sunak, French President Emmanuel Macron and Indian Prime Minister Narendra Modi.

Russia's invasion of Ukraine provides a backdrop to the summit, as Foreign Minister Sergei Lavrov attends instead of President Vladimir Putin.

Ukrainian President Volodymyr Zelenskiy addressed the summit virtually.

Leaders at the G20 summit took part in two closed sessions on health, food and energy security.

with Associated Press