Union leaders are meeting this week to discuss plans for organising employees that work for Wal-Mart in countries including the UK, Brazil, Argentina and Germany.
Forming a strategy will be discussed at the annual congress of the Union Network International (UNI), which collectively represents 15 million workers around the world.
Wal-Mart is the world’s largest employer with 1.6 million workers and has become a focus for trade unions. In the UK it owns the Asda chain, which recently had a skirmish with workers at a distribution centre in the North East.
The retailer is notoriously fiercely anti-union and is blamed by US trade unionists for depressing wages and benefits in both the retail sector and among suppliers.
A Wal-Mart spokeswoman said the firm would be interested to see “what type of dialogue they want to have”.
Less than 10% of Asda’s retail staff belong to a union. However, a spokesman told the Guardian newspaper in the UK that it “respected the right of colleagues to join a union”.