European Commission President Jean-Claude Juncker has praised outgoing British Prime Minister David Cameron and says he will miss him.

His words come despite a rocky start between the two when Cameron tried to block Juncker from becoming leader of the European Commission and warned that it would lead Britons to vote for Brexit.

Juncker told reporters in Beijing that the two of them had had "an excellent professional and personal relationship" since his appointment in 2014. He said he had "no beef" with Cameron, who steps down later Wednesday.

Juncker said: "I have experienced a man who is serious, who is a fan of no-nonsense policy and who was delivering at each and every moment when things started to become serious."