By Holger Hansen and Caroline Copley

WOLFSBURG, Germany (Reuters) - Germany appeared set on Monday to back an ambitious trade accord between the European Union and Canada after the leader of the Social Democrats (SPD), junior partner in the ruling coalition, overcame left-wing resistance to the deal within his party.

The SPD decision paves the way for EU member states to approve the Comprehensive Economic Trade Agreement (CETA) next month before Brussels signs the accord with Ottawa on Oct. 27.

Left-wing SPD members had argued that CETA would undermine workers' rights and environmental standards, but party leader Sigmar Gabriel said it represented the EU's best chance to shape globalization in the interests of ordinary people.

"It's a really good day for the SPD but especially for the implementation of rules for globalization," Gabriel told a news conference after two thirds of delegates at an SPD congress backed a compromise deal over CETA.

Gabriel, who is also vice chancellor and economy minister in Chancellor Angela Merkel's conservative-led coalition, has staked his political future on securing SPD backing for CETA.

Failure at Monday's congress, would have likely scuppered Gabriel's chances of standing as the SPD candidate for chancellor in national elections due in October 2017.

This might have unleashed a damaging power struggle within the SPD at a time when it is badly trailing Merkel's conservatives in opinion polls. The coalition's popularity has also suffered following Merkel's decision last year to open Germany's borders to more than one million migrants.

In a joint statement, EU Trade Commissioner Cecilia Malmstrom and Canada's Trade Minister Chrystia Freeland said they were committed to making "formal clarifications" on parts of the accord where there are still concerns.


Freeland later said neither side wanted to make changes.

"We are not reopening CETA. The negotiation is final, it is concluded," she told Canada-based reporters on a conference call. The clarifications, she added, would offer further guidance as to what the deal would encompass.

These include areas such as the delivery of public services, labor rights, environmental protection and an investment dispute settlement mechanism.

CETA aims to eliminate tariffs on 98 percent of goods immediately and also encompasses regulatory cooperation, shipping, sustainable development and access to government tenders.

It will require the approval of the European Parliament before taking effect, prior to ratifications by national parliaments which could take five years or more.

SPD critics of CETA see it as a blueprint for a parallel trade deal the EU is trying to negotiate with the United States, which is known as TTIP.

Around 180,000 people took part in rallies on Saturday in seven German cities against both trade deals, police said.

(With additional reporting by David Ljunggren in Ottawa; Editing by Gareth Jones and Cynthia Osterman)