Diplomats from several NATO states said Rutte, who was strongly backed by leading power the United States, will take over from current secretary general Jens Stoltenberg when his term ends on October 1.

Rutte, 57, last week sealed the race to lead the Western military alliance after lone challenger Romanian President Klaus Iohannis dropped out.

The seasoned Dutch leader, who is set to leave office in the Netherlands soon after almost 14 years in charge, will take the reins at a pivotal time.

The next NATO chief will have to grapple with the ongoing fallout from Russia's war on Ukraine and the potential return to the US presidency of Donald Trump after elections in November.