The G7's top diplomats arrived in the Japanese resort town of Karuizawa Sunday for talks set to be dominated by twin crises: China's growing pressure on Taiwan, and Russia's war in Ukraine.

There will be no shortage of diplomatic and security challenges to discuss for the foreign ministers, but recent regional events are likely to sharpen the focus on Asia.

The meeting comes days after China concluded major military drills around self-ruled Taiwan, and with Beijing barring ships from an area north of the island on Sunday.

On Thursday, North Korea launched what it said was a new solid-fuel intercontinental ballistic missile -- the latest in a stepped-up barrage of tests that have rattled nerves.

Host Japan is keen to ensure regional challenges top the agenda, and will emphasise its belief that Russia's invasion of Ukraine heightens the need for vigilance in Asia.

Japan's Prime Minister Fumio Kishida, whose government has revamped defence policy and spending in the face of growing Chinese power, has repeatedly warned that "Ukraine today could be East Asia tomorrow".

"Japan's basic position... on Ukraine is that the security of Europe and that of the Indo-Pacific cannot be discussed separately," a Japanese government official said ahead of the talks.

"They are intertwined with each other."

The G7 has regularly warned China against attempts to seize Taiwan, and individual members have sounded the alarm in recent days.

"A military escalation in the Taiwan Strait... would be a horror scenario for the entire world," German Foreign Minister Annalena Baerbock said Friday in Beijing.

But there will be renewed focus on the grouping's language after recent comments by French President Emmanuel Macron.

His insistence, after a trip to Beijing, that Europe should avoid "crises that aren't ours" has raised eyebrows and ire among Paris's allies, while delighting Chinese officials.

Paris has worked to temper the reaction, insisting France's views have not changed, and most observers expect the group to reiterate previous positions warning China against "changing the status quo by force".

- 'Freedom of manoeuvre' -

Still, Macron's comments expose a reality for the group -- Japan, the United States, Britain, Canada, France, Italy, Germany and the European Union -- said Paul Nadeau, adjunct professor of political science at Temple University's Japan campus.

"Each member of the G7 still wants a bit of autonomy in the way they pursue their relationship with China," he told AFP.

"They don't want to overcommit, they want to maintain some freedom of manoeuvre."

A senior US State Department official said discussions would reflect "collective concern about a number of the actions that China is taking".

"I think there will be a discussion of how we can continue to be fully aligned on a common and concerted approach," he said.

Consensus for the group, whose foreign ministers arrived by special bullet train to Karuizawa, will be easier on Ukraine.

The group is likely to again demand Russia's immediate withdrawal and pledge continued support for Ukraine.

It already imposed significant sanctions on Russia, so substantive new measures are not expected, though backing for a war crimes tribunal and fresh expressions of concern about Russian nuclear sabre-rattling are likely.

Both Russia's invasion and growing concerns about China have put renewed focus on economic security and the need to diversify supply chains for everything from energy to semiconductors.

Tokyo and Washington have warned about "economic coercion", and G7 ministers are expected to pledge measures to counter the issue.

The two-day meeting will also tackle international crises, from the Taliban's continuing grip on Afghanistan to the military junta's latest attacks in Myanmar.

Nuclear proliferation will also be up for discussion ahead of the leaders' summit in Hiroshima this May, where Kishida wants the push for a nuclear-free world to be a central topic.

He called Sunday for Japan to ramp up security to protect G7 events, a day after he escaped unharmed when an explosive was thrown at him during a campaign event.