BERLIN:  Germany, under fire from US President-elect Donald Trump for not meeting NATO's defence spending goal, is boosting military budgets, but also wants Trump to map out a consistent foreign policy agenda, Defence Minister Ursula von der Leyen said.

Trump sparked concern among NATO and EU foreign ministers on Monday when he said NATO was obsolete and criticised NATO members that failed to meet the alliance's target of spending two percent of national output on defence.

A key Trump adviser on Tuesday said only parts of NATO were obsolete, while Nikki Haley, his nominee for ambassador to the United Nations, said NATO was an important alliance and she did not believe it was obsolete.

"We want the Americans to be clear, 'What is your agenda,'" German Defence Minister Ursula von der Leyen told German broadcaster NTV. "The most important thing ... is reliability."

Von der Leyen said Germany was boosting military spending by nearly 2 billion euros in 2017 to 37 billion euros, or 1.22 percent of gross domestic product (GDP). It is due to reach 39.2 billion euros by 2020.

"We're moving in the right direction, but we can't do it in one year," she told NTV.

German Chancellor Angela Merkel said in November she did not expect Germany to meet its NATO defence spending target in the near future.

Von der Leyen welcomed support for NATO voiced by Trump's defence secretary nominee, James Mattis, during his Senate confirmation hearing.

"He's very reliable," she said, adding that the Trump administration still had to resolve some issues internally.

NATO Secretary-General Jens Stoltenberg told German newspaper Die Welt in an interview published on Thursday that Trump had assured him in a telephone call that the United States continued "to feel committed to NATO."

"I am absolutely certain the United States will continue to fully live up to its security guarantees for NATO," he said.

Asked about Trump's criticism that NATO had failed to prevent terror attacks in Europe, Stoltenberg said the alliance was already engaged in counter-terrorism efforts and talks were under way about how to expand that work.

A defence ministry spokesman said the German military's spending on weapons, munitions and other equipment rose by nearly 11 percent in 2016 to 5.1 billion euros and would increase even more sharply to 6 billion euros this year.

Procurement spending would account for 16.2 percent of the overall military budget in 2017, up from 14.5 percent in 2016 and 13.5 percent in 2015, the spokesman said.