OTTAWA -- Prime Minister Justin Trudeau says he expects the ambitious free trade deal between Canada and the European Union to be signed this year.

When it is it ratified later, it will be an important milestone in relations between Canada and the 28-country European block.

Canada's chief negotiator has said he expects the deal, known as CETA, to be ratified sometime next year.

Trudeau offered his assessment during a brief speech at an event marking the 40th anniversary of diplomatic relations between Canada and the European Union.

Earlier this week, Canada's chief CETA negotiator Steve Verhuel said Canada is working with the EU to revise controversial investor protection provisions in the deal at the direction of the Trudeau government.

The Europeans first raised the matter with Canada after political opposition arose in Europe in 2014 over the chapter that deals with settling disputes between companies and governments, known as ISDS, he said.

Trudeau didn't mention that bump in road but said his cabinet ministers have been instructed to work constructively with their European counterparts.

"The EU is the world's largest economy, largest donor of development and humanitarian assistance, and a central player in addressing global challenges," Trudeau said in a prepared text.

"I have encouraged my ministers -- many of whom are here tonight -- to work closely with the EU in delivering on their ambitious mandates for Canadians."