Starmer's visit is expected to include a bilateral meeting with Chinese President Xi Jinping, when some of those concerns -- including Beijing's alleged rights abuses, the war in Ukraine, and alleged spying -- could be apparent.

The British leader will then travel on to Japan on Saturday for a brief stop there, Tokyo's foreign ministry confirmed.

Starmer "will depart for his travel to China and Japan on Tuesday night", his spokesman told reporters on Monday, without providing further details of the much-anticipated trip.

"You can expect a range of issues to be raised, including but not restricted to trade and investment," he noted.

The visit spotlights Starmer's ambition to reset ties with China, an economic powerhouse, as the UK economy struggles and after relations between London and Beijing sank to new lows under the previous Conservative government.

The announcement of his visit comes less than a week after the British government approved contentious plans to build a "mega-embassy" in the heart of London.

The 20,000-square-metre (235,000-square-foot) site is set to become the largest embassy complex in the UK by area, and one of the largest in the centre of a Western capital.

But it could still face legal challenges and angry residents vowed last week to act.

Starmer himself last month acknowledged that while China provided significant economic opportunities for the UK, it also posed "real national security threats".

- 'Rethink alliances' -

There have also been protests by activists who fear the sprawling site in the historic former Royal Mint, next to the Tower of London, could be used to spy on and harass dissidents.

The UK government has said intelligence agencies have helped to develop a "range of measures" to manage any risks while Beijing has agreed to consolidate its seven current London sites into one, "bringing clear security advantages".

Bilateral relations plummeted in 2020 after Beijing imposed a sweeping national security law on Hong Kong, which severely curtailed freedoms in the former British colony.

Starmer is also expected to raise the case of Hong Kong media mogul and democracy supporter Jimmy Lai, 78, who is facing years in prison after being found guilty of collusion charges in December.

Starmer's trip follows finance minister Rachel Reeves's visit to Beijing last year, as the centre-left Labour government looks to improve trade relations and fulfil its primary goal of boosting UK economic growth.

The reset has faced domestic pushback, in particular from UK lawmakers who have been sanctioned by China for their criticisms of Beijing's actions in Hong Kong and over rights abuses.

Kerry Brown, who directs King's College London's Lau China Institute, told AFP that Starmer "may as well be getting something in return" for the flak he is taking.

"It is time for the UK government to really show that the reason for a pragmatic relationship with China is that it actually brings results that create jobs, help with the key priority of improving Britain's economy," he said.

Brown also noted it was an "excellent chance to try to work out the shape" of a new global geopolitics emerging due to US President Donald Trump's policies and volatile behaviour.

"Suddenly, we need to rethink the standard patterns and blocks of alliances," he noted.

"So in this context, China might not be an ally, but it is also not an enemy. It is a place that in some ways, has common reason to be as dismayed and appalled by the behaviour of the US as UK and other powers."