Steiner, who previously served at the UN Environment Programme and headed the UN office in Kenya, was selected to succeed Helen Clark, a former New Zealand prime minister, who has steered the UNDP since 2009, according to a letter by Guterres dated Tuesday.

Headquartered in New York City, the UNDP seeks to reduce poverty, improve social development and encourage women's empowerment.

One of the candidates passed over for the post included French Environment Minister Segolene Royal, who said she was surprised because Guterres had promised a woman would take the job.

She intimated that Germany used its weight as a major UNDP donor to have Steiner chosen.

"I regret it, of course. That doesn't gel with what was said, but c'est la vie," Royal told French television.