Reuters

Britain's Foreign Secretary Boris Johnson says Donald Trump's US presidential election victory offers economic opportunities and there's no need for Europeans to be despondent about it.

"I may respectfully say to my European friends and colleagues that it's time we snapped out of general doom and gloom about this election," Johnson said after meeting Serbian Prime Minister Aleksandar Vucic.

"He is after all a deal maker. He wants to do a free trade deal with the UK," Johnson told reporters.

Trump's shock victory over Hillary Clinton has delighted far-right politicians in France, the Netherlands and Austria but worried some mainstream politicians who fear it may be part of a populist, anti-establishment trend.

"I believe that this is a great opportunity for us in the UK to build on that relationship with America that is of fundamental economic importance for us but also of great importance for stability and prosperity in the world," Johnson said, setting aside his previous hostility towards Trump.

On Wednesday the former London mayor congratulated Trump on his victory and wrote on his Twitter account he looked forward to continuing the partnership between the two nations.

Last year Johnson said that he feared going to New York because of "the real risk of meeting Donald Trump" after the billionaire said parts of London were now so radicalised that police officers feared to go there.