European countries have been under intense pressure from an angry US President Donald Trump to share more of the burden in the world's biggest defence alliance and to meet this goal, as first promised to his predecessor Barack Obama in 2014.

Spending has increased in the six years since the pledge but major economy Germany still falls short -- and the coronavirus crisis has in any case taken a chunk out of the members' economies, making the two percent target easier to reach.

"This year will be the sixth consecutive year of increased defence spending by European allies and Canada, with a real increase of 4.3 percent," NATO secretary general Jens Stoltenberg said.

"We expect this trend to continue. Allies are also investing more in major capabilities and continue to contribute to our missions and operations," he told reporters, ahead of a defence ministers' meeting.

Germany has been a particular target of trump's ire, and this year its defence spending increased by 0.2 percent to 1.57 percent of GDP, but this was partly due to the epidemic reducing total output.

In real terms, NATO estimates German defence spending increased by $3.5 billion to $56 billion (47.5 billion euros).

In 2019, nine countries hit the two-percent target, and the United States leads by a wide margin in terms of defence spending, with 3.87 per cent of economic output.

At current prices, this is almost 785 billion dollars and thus more than two thirds of NATO members' total expenditure of around $1.092 trillion.

The US is followed by nine European countries that have reached the two percent target: Greece (2.58 per cent), Great Britain (2.43 per cent), Romania (2.38 per cent), Estonia (2.38 per cent), Latvia (2.32 per cent), Poland (2.3 per cent), Lithuania (2.28 per cent), France (2.11 per cent) and Norway (2.03 per cent).

France and Norway are new to the two percent club, but Bulgaria has dropped out again. Last year, the country increased its defence spending by leaps and bounds to 3.18 per cent. Now it is only at 1.93 per cent.