The European Union and Japan are rushing to ensure their planned free trade agreement can take force early in 2019, ideally before the British exit from the EU, the lead negotiators of both sides said on Wednesday.

Japan's ambassador for international economic affairs, Yoichi Suzuki, said the deal agreed to by negotiators last year would likely be presented to the Diet later this year, allowing ratification by year-end.

"It's a very high priority that it enter force before the end of March 2019," he said at a conference at the CEPS think tank in Brussels, referring to the date when Britain is set to leave the EU.