Major Japanese investors in Britain, including the three big carmakers, are due to meet the prime minister and chancellor later today.
A meeting is understood to have first been raised when Theresa May visited Japan last year.
But it comes amid fresh debate among business over Brexit negotiations.
Carmakers Nissan, Toyota and Honda were due to attend the talks, along with representatives from banks and drug companies.
The meeting is on Thursday afternoon and the attendees "will cover the most significant investors in the UK in such areas as banking, life sciences, technology and the manufacturing sector", a Downing Street spokesman said.
Japanese firms have spent billions of pounds in Britain over the past decades, encouraged to set up in the country by successive governments promising a business-friendly base from which to trade across the continent.
Nissan, Toyota and Honda began their UK operations in Britain in the 1980s and now build nearly half of all of Britain's 1.67 million cars. The big majority of these are exported.
The motor industry has expressed concern that their exports could face tariffs of up to 10% and be subject to customs delays after Britain leaves the European Union.
"Nissan Europe Chairman Paul Willcox will join representatives from other Japanese companies in meeting the prime minister and chancellor on Thursday to discuss our operations and investments in the UK," the firm said in a statement. "We will not be disclosing details of the discussions."
Japanese drug companies have also made Britain their European base. Some are concerned about future drug regulations, with any divergence with the EU likely to pose regulatory challenges.
London is also home to Japanese banks, such as Nomura, Daiwa Securities and Sumitomo Mitsui Financial. Like other foreign banks, they are keen to know about trading and so-called "passporting" arrangements for access to the EU.
In 2016 Nissan chief executive Carlos Ghosn met prime minister Theresa May amid fears over the future of its production plant in Sunderland.
Nissan sought assurances over post-Brexit arrangements ahead of future investment in the Sunderland plant, Britain's biggest car factory.