LONDON (BLOOMBERG) - Mr Boris Johnson's plan to host an expanded Group of Seven (G-7) summit in June is worrying some other members who fear the UK may be trying to reshape the forum of wealthy nations via the back door.

The British prime minister has invited South Korea, India and Australia as guests to this year's meeting as he tries to establish a so-called D-10 coalition of democracies to counter China and other authoritarian states.

Mr Johnson wants to champion global action and democratic values, and project the UK as a force for good after leaving the European Union.

While it is standard practice for a G-7 host to invite more countries to the summit, the involvement of guest nations is typically limited.

According to a person familiar with Mr Johnson's plans, that will change this year with the three countries set to take part from the get-go, from preparatory meetings of the leaders' diplomatic emissaries early next month through to ministerial gatherings before the summit.

Though diplomats are waiting to understand the full implications, there's some concern Mr Johnson's D-10 is a step toward restructuring the G-7.

One diplomat said a rival grouping risks weakening the G-7, and that could eventually raise pressure on the G-7 to expand in order to regain its lost influence. Expansion is an idea Italy, Germany, France and Japan oppose, according to officials familiar with those governments' positions.

China risk

Two European diplomats also warned there's a risk that anti-China rhetoric foments a Cold War-style standoff with Beijing, which both said the G-7 must avoid after it batted away Mr Donald Trump's attempts to do the same.

One diplomat said there would be doubts within the group about whether a UK idea established for domestic reasons would have any staying power. The UK government didn't respond to a request for comment.

The issue of expanding the G-7 cuts to the heart of questions about the future of the forum and where members' strategic interests lie, especially on China.

This year's summit is a chance to repair ties after years of splintering in the Trump era. The outgoing US president refused to sign the end-of-summit communique in Canada in 2018, while last year's meeting - which Mr Trump was meant to host - never took place.

Mr Johnson intends to put issues including climate change - so undermined by Mr Trump - at the centre of this year's summit along with trade, health, press and religious freedoms, and human rights.

Reassurance

According to diplomats, the club's other six members welcome those aspirations, and also want to cooperate on the post-pandemic recovery.

The UK has also assured members it has no plans to propose changes to the G-7 format and that it will remain distinct from the wider group of democracies, according to three diplomats familiar with the matter.

That hasn't fully assuaged G-7 members' concerns.

One of the diplomats said while there is no immediate prospect of extending the group, once institutionalised the D-10 could compete with the G-7 for relevance. Another said the UK must consult closely with G-7 members about its plans for the D-10 coalition.

Another official said some of those concerns are shared but that the full extent of the guests' role is not clear, and the three countries would not participate in all the preparatory work. The same official also pointed out that expanding the G-7 would require unanimity, making it unlikely anytime soon.

Trump effect

The debate over reformatting the G-7 isn't new, and the expansion idea was floated by Mr Trump last year. In addition to Australia, South Korea and India, he proposed re-inviting Russia, which was ejected after the annexation of Crimea.

President-elect Joe Biden hasn't indicated where he stands on the issue but has said he wants to convene a summit of democracies once in office.

Prominent voices on both sides of the Atlantic continue to push for the G-7 to open its doors to new members.

Mr Tobias Ellwood, chair of the House of Commons defence committee, said this month an expanded G-7 including Australia, India and South Korea "can begin to address and reverse the demise in global stability, democratic values and rule of law."

Johnson's agenda has potential sticking points beyond the expansion debate. South Korea's participation is awkward for Japan given renewed tensions stemming from its 1910-1945 colonial rule over the Korean Peninsula.

UK and European diplomats also point to geopolitical differences. A British diplomat said that having left the EU, it makes economic sense to improve ties with Asia-Pacific nations including those in the 10-member Association of South-east Asian Nations (Asean), with whom the UK is seeking a partnership status and which is also expected to be invited to the G-7 leaders' summit.

It should also be seen in the context of a more robust approach toward China compared with that of the EU, the diplomat said. Since decoupling from the bloc's trade policy, Britain has been more outspoken on China and Hong Kong.

Meanwhile the EU has faced criticism, including from the incoming Biden administration, for agreeing a trade deal with Beijing. Officials in Brussels and some European capitals argue trade should be kept separate from issues that can be dealt with using other tools, such as sanctions.

Two European diplomats said the narrow focus on the Asia-Pacific region relegates areas of strategic interest to Europe, including Africa, and ignores regions like Latin America.