Japanese Prime Minister Fumio Kishida has held a bilateral meeting with Italian counterpart Giorgia Meloni, a day before the G7 leaders' summit kicks off in Hiroshima.

At the meeting, the two leaders agreed to deepen their ties as Italy will take over the G7 presidency from Japan in 2024.

Kishida also expressed his condolences after recent torrential rain battered Italy's northern Emilia-Romagna region, where nine people died and thousands were evacuated.

"I heard that people have died due to torrential rains in the Emilia-Romagna region," he said.

"I would like to express my heartfelt sympathy for the severe damage, and I sincerely wish for its speedy recovery."

Meloni arrived in Hiroshima early on Thursday and will attend the three-day G7 summit with other leaders from Friday.

"We have agreed to upgrade our strategic partnership between Japan and Italy, and I would like to proceed with detailed cooperation in the future," Kishida said.

Meloni agreed, adding: "As you've mentioned, since Italy is the next president (of the G7 summit), it's even more essential for us to deepen our cooperation."

Italy's Prime Minister Giorgia Meloni holds a bilateral meeting with Japan's Prime Minister Fumio Kishida. – Reuters

Meanwhile, the British, Canadian and German leaders arrived in Hiroshima for the leaders' summit, which will discuss geopolitical, economic and climate issues.

Canadian Prime Minister Justin Trudeau, German Chancellor Olaf Scholz and British Prime Minister Rishi Sunak were greeted by Japanese officials upon landing at the airport, before leaving in their respective motorcades.

As the heads of the world's advanced democracies meet for three days from Friday in Hiroshima, they will need to overcome some differences of their own, officials say, as they aim to project unity against challenges from Beijing and Moscow.

Divisions within the G7 appear to be the most notable over China, multiple officials said, with countries grappling on how to warn against what they see as China's threat to global supply chains and economic security without completely alienating a powerful and important trade partner.

The G7 countries – the United States, Japan, Germany, the United Kingdom, France, Canada and Italy –- are all closely tied economically to China, the world's second-largest economy and a key global manufacturing base and market.

Canadian Prime Minister Justin Trudeau, German Chancellor Olaf Scholz and British Prime Minister Rishi Sunak arrive in Japan. – Reuters