Lawmakers in the small Belgian region of Wallonia on Friday voted to block an EU-Canada free trade deal, a move which could seriously complicate future talks with the US and a non-EU Britain.

The parliament vote in the French-speaking part of southern Belgium threatens to derail the long-delayed signing by Canadian Prime Minister Justin Trudeau of the pact, known as CETA, in Brussels later this month.

"I will not give powers to the federal government and Belgium will not sign CETA on October 18," Paul Magnette, the socialist head of the Wallonia government, told an emergency session of the regional parliament.

"I do not intend this as a burial but as a demand to reopen negotiations," said Magnette, who is under huge international pressure to reverse his position.

After talks in Paris with French President Francois Hollande, Magnette later hinted he was ready for a solution.

"I am a natural optimist and very willing. What we are asking for is very reasonable," Magnette added.

"What there has to be for us is legal clauses so that there will be no conflicts between companies and states, that we can protect the powers of the state and our public services," he said.

In a largely expected vote outcome, 46 MPs in the economically depressed area voted to reject the trade deal, with 16 against the motion and one abstention.

Linguistically-divided Belgium's seven different parliaments must first give the federal government power of signature for Belgium to give its official approval, under the country's complex political system.

In order to be signed by Trudeau at the EU-Canada summit on October 27, the deal must first be backed by all 28 EU member states at a trade ministers' meeting on Tuesday.

"I am worried about the future of Europe; why add another crisis?" said Belgian Foreign Minister Didier Reynders, who still hopes to approve the deal on Tuesday.

- 'It's incomprehensible!' -

Trudeau on Wednesday said he was running out of patience after two years of delays and warned that killing the deal would send "a very clear message... that Europe is not productive".

Poorer, industrial Wallonia has grown increasingly protectionist in stark contrast to richer, Dutch-speaking Flanders in the north, which eagerly embraces globalisation.

Belgium's complex political system includes a federal parliament, parliaments for the three regions of Flanders, Wallonia and Brussels-capital, and legislatures for Belgium's Flemish, French and German-speaking communities.

Magnette later held talks in Paris with French President Francois Hollande, the EU's most powerful socialist leader and who backs the deal.

Belgium's federal and Flanders' parliaments have already indicated that they will back the accord.

"It's incomprehensible," said Geert Bourgeois, head of the Flanders region, told Belga news agency.

The Wallonia government "stands isolated on the European and international scene," he said.

Activists charge that the Canada deal will set a dangerous precedent and open the way for a similar but far more ambitious agreement with the United States, the Transatlantic Trade and Investment Partnership (TTIP).

TTIP has already run into trouble, with the EU saying it will not be agreed before President Barack Obama leaves office in January, as was initially planned.

"This parliament truly defends its citizens, not the interests of lobbyists and corporations," said Vincent De Brouwer of Greenpeace Belgium.

"It is now up to the European institutions to listen to this signal and bury these dangerous treaties," he added.

The problems getting the Canada deal through Belgium's political maze is also a trial run for the even more controversial negotiations over Britain's exit from the EU.

Whatever deal is reached for Brexit after two years of negotiations, expected to start in March, must also be passed by all EU parliaments -- including Belgium's seven.