BRUSSELS--The European Union is very close to finalizing a free trade deal with Japan and believes it can agree the key elements of pacts with Mexico and Latin American bloc Mercosur by the end of the year, the EU trade chief said on Thursday.

The European Union and Japan agreed the outlines of a trade accord in July, which would open up the EU to Japanese cars and car parts and Japan to EU cheese.

"We are very close to finalizing. There are a few small technical issues, there's always the devil in the detail at the end. If all goes well we can conclude this year," Trade Commissioner Cecilia Malmstrom told a briefing on Thursday.

The two parties remain stuck over the issue of investment protection, with Japan reluctant to adopt the investment court system the EU has devised as an answer to fierce criticism that disputes between foreign companies and states should not be settled by opaque tribunals.

"The Japanese are rather fond of the old system... So this will probably have to continue next year, but we could conclude the trade agreement. They could be separated," Malmstrom said.

In essence, a trade-only agreement could be struck, with discussions on investment protection resuming early next year.

"This is an important partner, an important economy and it will send a powerful signal," Malmstrom said, adding she hoped it could then be approved by 2019.

The European Commission, which negotiates trade pacts on behalf of the EU's 28 members, is also hoping to have agreed the main elements of an updated deal with Mexico and a new accord with Mercosur members Argentina, Brazil, Paraguay and Uruguay.

The EU and Mexico will hold a next round of negotiations in Brussels from Dec. 18. Malmstrom said it was possible to conclude those talks "right before Christmas or just after."

Before then, she will travel to Buenos Aires for a World Trade Organization meeting starting on Sunday and will seek to bridge the last differences with Mercosur ministers.

"We know what we want to do. The question is will we have time to do that before the end of the year or not. The ambition is to conclude before the end of the year, but if that is not possible it's not a disaster," she said.