Turkey on Monday informed Brussels it supported outgoing Dutch Prime Minister Mark Rutte's bid to become the next secretary general of NATO, foreign ministry spokesman Oncu Keceli said.

Rutte met President Recep Tayyip Erdogan in Istanbul on Friday to rally Turkey's support for his candidacy.

The Dutch politician is the frontrunner to replace Norwegian Jens Stoltenberg at the helm of the military alliance after Britain, Germany and the United States voiced their support for his candidacy.

"Today we informed Brussels," Keceli told AFP of the government's support for Rutte.

Romanian President Klaus Iohannis is also a candidate for the NATO post.

In Istanbul, Erdogan said Turkey's decision would be based on "reason", while smilingly wishing Rutte success on his "new journey".