Sir Philip Green's clothing empire has been criticised for shunning a new initiative aimed at improving safety standards at Bangladeshi clothing manufacturers in the wake of the Rana Plaza disaster in April.

The tycoon's brands, which include TopShop, BHS and Miss Selfridge, are notable absentees from a list of supporters of the Bangladesh Safety Accord, which is backed by 80 top high street brands ranging from Marks & Spencer and Next to Primark and H&M.

The scheme, which was unveiled in May and is co-ordinated by the UN's International Labour Organisation (ILO), has seen retailers agree to a range of measures including inspections of suppliers to identify "grave hazards and the need for urgent repairs", as well as companies committing to hiring chief safety inspectors to inspect standards at all factories producing garments for the participating brands.

Murray Worthy, of the anti-poverty campaign group War on Want, said: "TopShop's bosses have got no excuse for not signing this agreement. With their bumper profits, they can easily afford a tiny fraction of that to make their supplier factories safe. Their failure to act and to work with other UK high street retailers to make these factories safe leaves thousands of workers' lives at risk."

A spokeswoman for Arcadia, the holding company of Green's retail brands, said: "Arcadia are in continued and detailed discussions with the Bangladesh Accord steering group. An Arcadia representative attended a [Department for International Development] round-table session on Bangladesh, and we are undertaking robust measures to ensure suppliers and factories we work with in Bangladesh are compliant with our own stringent code of conduct, whilst being fully supportive of industry initiatives."

The move to address safety within Bangladesh's manufacturing industry came after 1,127 workers were killed in April following the collapse of a clothing factory in the Dhaka suburb of Savar. In a second incident, eight people were killed in a fire at a factory in the capital that was producing clothes for western retailers including Primark. It is estimated that at least 1,800 garment industry workers have been killed in fires or building collapses since 2005.

At the Accord's launch in May, Krishan Hundal, director of sourcing at M&S, said: "We recognise the need for a safer garment industry in Bangladesh and have signed the accord on fire and building safety. We will play our role alongside the ILO, other clothing brands and NGOs in developing it into an effective programme to deliver a better working environment across all 5,000 garment factories in Bangladesh."