Walloon MPs say Ceta favours Canadian firms and they want more safeguards for Belgian farmers.
It is the EU`s biggest trade deal yet.
Going into the Luxembourg meeting, Mr Reynders said: "The federal government is in favour [of Ceta] but we have to convince particularly Wallonia.
"I`m in permanent contact with the Walloon prime minister. I hope we`ll be able to move forward at the summit."
Trade will be a major issue at the two-day EU summit in Brussels, which starts on Thursday.
Brexit implications
EU leaders hope to sign Ceta - the Comprehensive Economic and Trade Agreement - with Canadian Prime Minister Justin Trudeau on 27 October. The negotiations started in 2009.
Some UK politicians see Ceta as a possible model for a Brexit deal with the EU. It will not allow the degree of EU market access that UK services currently enjoy. And Ceta does not involve EU-style free movement of people.
Walloon PM Paul Magnette said he was expecting the European Commission to present an additional text addressing his region`s concerns.
On Friday the Walloon parliament, representing 3.6m people, voted against Ceta.
More about:
-1780923278.jpg&h=190&w=280&zc=1&q=100)
