Obama says having Antonio Guterres as UN secretary-general will be important as worldwide challenges and uncertainty continue to mount. (Source: AP)

President Barack Obama says the former Portuguese prime minister who will lead the UN beginning January 1 has already proven to be an effective leader.

Obama says having Antonio Guterres as UN secretary-general will be important as worldwide challenges and uncertainty continue to mount. Guterres is also the UN’s former refugee chief. He was elected in October to succeed Ban Ki-moon.

Meeting with Obama at the White House, Guterres expressed “total commitment” to working closely with Obama and President-elect Donald Trump.

Guterres says the world needs a UN that’s more effective, more cost-effective and adopts a strong, reform-minded approach. He says he’s committed to that objective, which the US has long shared, to make sure the organisation can be a “positive partner” with the US.