Labour rights groups are continuing to put pressure on retail giants Gap and Walmart to join the Bangladesh Safety Accord, with weekend demonstrations organised outside their stores in 35 cities across the world.

The action was led by United Students Against Sweatshops (USAS), joined by United Steelworkers, Service Employees International Union, International Labor Rights Forum, and other unions and community groups.

Protesters want the retailers to join the legally-enforceable Bangladesh Safety Accord, which has so far been signed by at least 60 brands and retailers, including H&M, PVH and Abercrombie & Fitch.

Gap and Walmart, however, are instead focusing on their own measures to tackle problems in Bangladesh's garment industry.

The Bangladesh Safety Accord requires independent inspections by trained fire safety experts, mandatory repairs and renovations financed by the brands, and a central role for workers and unions.

The Worker Rights Consortium estimates that the costs of factory renovations for Walmart would be just two-tenths of 1% of the company's profit last year, and 1% of the dividends paid out last year to the Walton family heirs.

For Gap, it says the costs represent, at most, just 0.8% of Gap's profits last year, and 1.5% of the net wealth of Gap co-founder Doris Fisher.

The demonstrations occurred just days after the US suspended preferential GSP trade benefits for Bangladesh in response to deteriorating labour conditions in the country.

USAS is North America's largest student-run campaign organisation, with affiliates on over 150 college campuses advocating for the rights of workers making college apparel.

A recent campaign by students led to 17 universities and colleges across the US ending their contracts with Adidas until it agreed to compensate more than 2,500 Indonesian garment workers from a closed PT Kizone factory producing collegiate apparel.