US President Barack Obama arrives at the Tegel airport in Berlin, Germany, November 16, 2016. [Photo/Agencies]

US President Barack Obama arrived in Berlin on Wednesday to meet German Chancellor Angela Merkel, with whom he has forged a close transatlantic alliance during eight years in office that President-elect Donald Trump may now call into question.

Obama, who described Merkel ahead of the visit as his "closest international partner", will dine with the chancellor at Berlin's famous Adlon hotel directly next to the landmark Brandenburg Gate on Wednesday evening.

The two leaders, who together tackled the global financial crisis, promoted free trade and forged an international accord to fight climate change, stressed their shared values in a joint guest piece for German magazine Wirtschaftswoche.

"There will be no return to a world before globalisation," they wrote, stressing the benefits of a free trade deal being negotiated between the European Union and the United States.

Trump, a billionaire businessman with no previous experience of public office, made attacks on international trade deals a cornerstone of his election campaign, saying they have cost US jobs.

Merkel and Obama will hold bilateral talks on Thursday before they are joined on Friday by the leaders of France, Britain, Spain and Italy.

It is Obama's last trip to Europe as president before he hands over to Trump in January.