Sir Keir Starmer has confirmed he will meet Chinese President Xi Jinping as he wants a “pragmatic and serious” relationship with Beijing.
The Prime Minister will become the first UK leader since Theresa May in 2018 to meet the Chinese premier.
They are expected to hold talks on Monday at the G20 Summit in Brazil.
Downing Street said Sir Keir wants to build “pragmatic partnerships with other countries, even where our values differ”.
But critics are concerned about the prospect of cosying up to Beijing at a time of heightened geopolitical tension.
China is bolstering its army and navy, warning it could invade Taiwan, and is supporting Russia’s invasion of Ukraine by effectively keeping Vladimir Putin’s economy afloat.
Sir Keir said: “I am planning to have a bilateral with President Xi at the G20.
“I think that’s important. We are both global players, global powers, both permanent members of the Security Council and of the G20.
“China’s economy is obviously the second-biggest in the world. It’s one of our biggest trading partners and therefore I will be having serious, pragmatic discussions with the president when I meet him.”
Asked if he wants better diplomatic relations than under previous regimes, Sir Keir said: “Given the size of the economy, it is very important that we have a pragmatic and serious relationship and that’s what I intend to pursue.”
Pressed on whether he thought the Chinese premier was guilty of genocide, the Labour leader added: “I think Rishi Sunak used in his very last PMQs or the one before to ask me about China, so there’s a whole series of answers there in terms of my position.
“But I do think it’s important that we have serious engagement, which is what I will be pursuing in my bilateral at the G20.”
The discussions are likely to focus on trade and areas of mutual interest, such as climate change and international stability.
No 10 insisted Sir Keir “will be firm on the need to have honest conversations on areas of disagreement, while competing and challenging where we have to”.
Chancellor Rachel Reeves is also expected to visit China in the new year as the Government tries to revive the economic and financial dialogue between the two countries.
The value of UK exports to China has increased from £20billion in 2016 to £33billion last year, despite the challenging political situation.
Speaking as rumours of the meeting emerged over the weekend, former Tory leader Sir Iain Duncan Smith told the Daily Express: “President Xi has no regard for the UK and is trashing all the rules-based order around the world, from human rights, to the WTO [World Trade Organisation], China just ignores what it is told.
“President Trump believes China is a threat to Western values and I happen to agree with him. I think they are.
“China has 230 times the shipbuilding capacity of America now. Only one shipyard in China can outbuild all of the United States.
“They are building up their army and when it comes to commerce, lots of middle-ground companies are leaving China and there’s a reason for that.
“China steals their IP, trashes their businesses and has no regard for WTO rules.”