European Commission chief Jean-Claude Juncker said Friday he will "do everything" to secure a deal with the South American trade bloc Mercosur by the end of the year.

"This will be the most important trade agreement in terms of volume," he said at a closing press conference at a European summit in Brussels.

"A good agreement with the Mercosur countries -- it's worth eight times more than the agreement with Canada and four times more than the agreement with Japan."

The EU and Mercosur, which includes several South American countries including Argentina and Brazil, have been trying to negotiate an agreement for many years. 

Juncker's intent to push towards a conclusion of the talks with Mercosur comes as French President Emmanuel Macron called on Brussels to moderate its zeal to conclude free trade deals.

On Friday, Macron asked for "a balanced policy between openness and protection" in a bid to stop slumping support for free trade. Recent deals have been seen as costing European jobs and undermining health and safety guarantees.

In order to reach a deal with Mercosur, Brussels has signalled it is ready to make concessions with the bloc on beef and ethanol in exchange for more market share for its cars.

The EU has also revived discussions with Mexico and pledged to fast-track free trade talks with Australia and New Zealand, and would do so by bypassing the risky national ratification process that could torpedo a similar deal with Canada.