Thousands of Bangladeshi garment workers demanded justice on the anniversary Sunday of one of the world's worst industrial disasters, the collapse of the Rana Plaza factory complex that claimed over 1,100 lives.

Survivors of the disaster, many of whom lost limbs when the nine-storey building came crashing down three years ago, laid flowers at the site and wept as they remembered the dead.

Relatives of those killed, including some whose bodies were never found, recited verses of the Koran and prayed after gathering from early morning at Savar just outside Dhaka.

‘Three years have passed and still we don't see any justice. No one has been held to account for one of history's worst man-made disasters,’ union leader Abul Hossain said as he led the protest.

Police have arrested and charged the owner of the building with murder, along with 40 others -- including factory officials and government inspectors who certified the flimsy complex as safe.

But no one has yet been convicted over the disaster, which ocurred after thousands of textile workers were forced to enter the building to start their shifts despite cracks appearing in its pillars one day before.

Workers also staged protests in Dhaka on Sunday and outside a state graveyard where hundreds of unidentified victims have been buried, to demand swift trials for those charged.

‘Rana must be hanged!’ workers shouted, referring to arrested building owner Sohel Rana who was politically influential in Bangladesh.

Others who gathered at the disaster site, which has been turned into a small lake and was Sunday full of hyacinth flowers, called for improved safety at Bangladesh's 4,500 garment factories.

‘The government must shut down all faulty factories to avoid another Rana Plaza. It's unfortunate most factories remain unsafe despite such a huge tragedy,’ said another union leader, Touhidul Islam.

The Rana Plaza tragedy triggered international outrage and put pressure on European and US clothing brands to improve pay and conditions at the factories that supply them.

But only a fraction of Bangladesh's textile factories -- which employ a total of four million workers, mostly women -- have since been certified safe.

- 'Scenes of carnage' -Last year the authorities completed compensation payments for the 3,000 victims, including the injured and families of the dead, but many survivors say it is not enough.

‘I got 4,000 taka ($50) a month for two years. But now I don't have anything. My husband has left me as I've become mentally unstable,’ said Swapna Bibi, 25, who was trapped in the rubble for four days.

Firefighters were also among those who gathered, recalling how they worked for more than three weeks to pull out the dead and nearly 2,000 injured from under pancaked floors.

‘The memories of those who cried for help from under the debris still haunt me and many others,’ said weeping firefighter Monir Hossain.

‘I've never seen scenes of carnage like this. I saw workers dying one after another as they were trapped under fallen pillars or debris. I was so overwhelmed I had to be hospitalised with mental problems,’ he said.

At the site dozens of people held laminated photographs of missing loved ones whose bodies were never found.

‘Our sole request to the government is please find my sister's body so that my mother, who has been sick, can die in peace,’ said Lipy Begum, whose sister Kulsum Begum, 16, has been declared dead.