Three workers died and more than 70 suffered serious injuries building Dubai's Expo 2020 site, officials said on Saturday, insisting safety standards were "world-class".

The figures were revealed after the European parliament called for a boycott of the six-month world fair, criticising the United Arab Emirates' human rights record and "inhumane" practises towards immigrant labourers.

More than 200,000 workers constructed the huge site on the outskirts of Dubai, which features hundreds of pavilions and other facilities on a showground twice the size of Monaco.

The UAE and fellow Gulf nation Qatar, host of next year's World Cup, are frequently in the crosshairs of activist groups over their treatment of labourers, often from South Asia, who build their ambitious developments.

"Unfortunately, there have been three work-related fatalities, 72 serious injuries to date," an Expo statement said, calling the welfare of labourers its "top priority".

It said 247 million work hours had been completed at the site, adding that the frequency of accidents was lower than Britain's.

"We have established world-class policies, standards and processes that protect and support the health, safety, and wellbeing of everyone involved in Expo 2020 Dubai," the statement said.

French Foreign Minister Jean-Yves Le Drian, who visited Expo on Saturday, said France was "not part of" the European parliament's resolution.

"Our relation with UAE is a strategic one, it's very close, and we can say things in all transparency and if we need to say something to UAE government, well we do so but behind close doors," he told reporters.