Berlin and Tokyo will move closer to defend the "multilateral order", on which the two big exporters' fortunes rest when German Chancellor Angela Merkel kicks off her two-day visit to Japan on Monday, observers said.

"As the world's third-and fourth-largest economies as well as big exporters, Japan and Germany are beneficiaries of free trade and multilateralism," said Yu Qiang, a researcher of Japan studies and an associate professor at the University of International Relations in Beijing, adding that the two countries had drawn closer amid US President Donald Trump's "America First" approach.

"We hope the chancellor's visit will send a message that Japan and Germany will actively contribute to the rule-based prosperity of the global economy, and further deepen bilateral cooperation and relations of trust," Japanese Chief Cabinet Secretary Yoshihide Suga told a news conference several days ago.

Last week in Davos, Switzerland, Merkel advocated before world leaders "win-win" outcomes in international relations, while Japanese Prime Minister Shinzo Abe vowed to rebuild trust in the global trade system.

"Another mindset is now also represented on the world stage," Merkel warned in her speech at the World Economic Forum in Davos.

"One claims that the world works best if everyone thinks of themselves and puts their own interests first.

"(To this) I have my doubts," she said, adding that national interests must factor in the interests of other countries and that "win-win situations are the prerequisite for multilateral action".

Yu said Merkel's visit to Japan is most likely to back up her words in Davos and to forge a strong bloc of "multilateralists" with like-minded leaders like Abe.

"The visit gives the chancellor the opportunity to strengthen the relationship with Japan," a senior German government official was quoted by Reuters as saying before the trip.

"It also gives both sides an opportunity to send a strong signal that we and Japan are maintaining a close and resilient partnership even under global political conditions that have become more difficult," he said.

Monday's visit will be Merkel's fifth time to Japan since taking office in 2005. Her last visit was in 2016. This time she is expected to meet Japanese Emperor Akihito, who plans to abdicate in April.