(Updates with details of German opposition and of law)

BRUSSELS, Feb 28 (Reuters) - European Union countries blocked at a late stage on Wednesday a proposed law requiring large companies in the bloc to check if their supply chains use forced labour or cause environmental damage.

A 'qualified majority' of 15 EU countries representing 65% of the EU population had been needed for the corporate sustainability due diligence directive (CSDDD) to proceed to a final vote in the European Parliament. Lawmakers were expected to support it.

On Wednesday, not enough envoys from the 27 EU countries backed the law for it to proceed, with opposition led by Germany's pro-business Free Democrats, part of the three-party governing coalition, who argued it would burden business with excessive bureaucracy.

This was the second time Belgium, which holds the rotating EU presidency, had tried to secure backing for a text already agreed with the European Parliament. Earlier this month, it withdrew it from the agenda at the last minute after Germany and Italy indicated they would abstain.

Belgium said in a posting on X social media that it would see if it was possible to address concerns of EU members, in consultation with the parliament.

Germany, once the engine of EU integration with France, has already criticised an EU law to end sales of CO2-emitting cars by 2035 and on EU plans to reduce truck emissions.

Under the CSDDD, designed to enter force in 2027, large companies in the European Union would have to identify and remedy in their supply chains cases of employing forced or child labour or environmental damage, such as deforestation. (Reporting by Philip Blenkinsop, Charlotte Van Campenhout Editing by Alexandra Hudson)