France and Germany outlined separate proposals for reforming NATO on Wednesday after President Emmanuel Macron slammed the alliance as experiencing "brain death", causing uproar just weeks before a crucial summit.

French Foreign Minister Jean-Yves Le Drian used the one-day meeting with his 28 NATO counterparts to explain Macron's damning verdict and offer ideas for improvement.

Macron argued in an Economist interview that Turkey's military incursion into Syria and US unpredictability under President Donald Trump indicated a failure of strategic thinking at NATO.

Le Drian suggested a "small group of eminent persons" be formed to reflect on "the vision the alliance has of its values and aims" and report back to leaders at their summit in 2021.

The experts should focus on NATO's relationship with Russia and the future security challenges -- in particular terrorism, the rise of China and the impact of new military technology, Le Drian told the ministers.

In a sign of the ongoing tensions with France, NATO chief Jens Stoltenberg, who will next week confront Macron in person about his comments, refused three times to comment on the French proposal at a press conference after the meeting.

But he welcomed a separate plan from German Foreign Minister Heiko Maas to create a group of experts to debate how to strengthen NATO's political thinking.

"The proposal from minister Heiko Maas received support from many allies and I think it has value," he said, adding that it would be examined further ahead of the December 4 summit in London.

Maas said the discussion among the 29 allies made him think Germany had "hit the right note" with its plan for a committee chaired by Stoltenberg himself.

US Secretary of State Mike Pompeo said it was "eminently reasonable" for NATO to evaluate itself to ensure it was fulfilling its goals, but questioned whether "this is precisely the right moment or if this is the right format".

NATO has not had a happy 70th birthday year. Macron's comments came alongside Trump's insistent complaints about weak European defence spending and growing concerns about Turkey, which has bought missiles from Russia and launched a military operation in Syria with scant regard for allies.

French officials insist Macron made a bold and necessary step by starkly spelling out truths that other allies preferred to gloss over.

NATO Secretary General Jens Stoltenberg refused to comment on the French proposal
NATO Secretary General Jens Stoltenberg refused to comment on the French proposal AFP / Kenzo TRIBOUILLARD

But Macron's arguments that Europe should try to ensure its own security without relying on the US provoked anger from eastern European allies who feel directly threatened by Russia.

Diplomats from other countries point out that it is for now wholly unrealistic for Europe to think it can defend itself without US help -- expert estimates suggest filling the gap would cost hundreds of billions of euros.

"There is currently no credible alternative to NATO. We need American capabilities," one diplomat said.

Away from the political wrangling, foreign ministers prepared the agenda for next month's summit, lining up a series of announcements to put a positive gloss on the gathering.

"The damage has been done, now we have to limit the fallout to put on a united front in London," one senior diplomat said.

They also hope that some eye-catching actions will appease the mercurial US president, who will arrive at the summit under the cloud of impeachment hearings back home.

The ministers formally designated space as a domain of conflict -- alongside land, sea, air and cyber -- though Stoltenberg insisted NATO would not "weaponise" space.

They also signed off a report on China featuring some 24 different areas for allies to work on, though the paper will not be made public.

While China lies well outside NATO's traditional European-Atlantic sphere, Stoltenberg said Beijing's growing role as a major military power and heavy investment in new defence technology had implications for alliance security.

He declined to comment directly on the ongoing political protests in Hong Kong but said it was clear China does not "share our values when it comes to elections, freedom of speech".

Trump's bugbear -- European defence spending -- will also feature heavily in London.

NATO will be hoping Germany's announcement last week of a boost for its military spending will go some way to head off a repeat of the 2018 Brussels summit, when Trump publicly berated Chancellor Angela Merkel for not doing enough on defence.