The death toll in a disastrous collapse of a rubbish dump in Sri Lanka rose to at least 29 on Monday, as traumatised residents accused authorities of ignoring their previous warnings over the site's safety.

Rescuers continued digging through heaps of mud and rubbish that collapsed on to a clutch of homes near a rubbish dump just outside Sri Lanka's capital, killing at least 29 people and possibly burying dozens more.

Hundreds of people had been living in the working-class neighbourhood on the fringe of the towering dump in Meetotamulla, near Colombo, when a huge mound collapsed on Friday night during a celebration for the local new year, damaging at least 150 homes.

AL JAZEERA'S MINELLE FERNANDEZ IN MEETOTAMULLA, NEAR COLOMBO: "There is not much hope of finding survivors from what we're hearing from rescue authorities and residents around the area. Some came back to the scene of the disaster to let it sink in as to what's happened to their homes, which were swallowed by this huge mound of garbage. A lady we spoke to who was in charge of the area said she couldn't even recognise the terrain here. She said all the two-storey houses were completely swallowed. Residents are very angry and traumatised; they said this was an absolute disaster waiting to happen. According to one estimate, there were 23 million tonnes of garbage which built up over many years - it's not something that started recently. From time to time, people have barricaded roads, set fire to things, spoken to politicians, conducted sit-down protests. They were assured that something would be done. We had one assurance by the municpal authorities that dumping here would stop back in 2013 and we are now in 2017. Until Friday, when this disaster happened, there were still lorryloads of garbage brought here. Many say this could have been prevented if authorities had seen the scale of the disaster. Every time there are heavy rains, the garbage becomes saturated and then slides and slips. The houses that fell were at the doorstep of this garbage. Government officials say they have just signed agreements with Japanese experts to look at solid waste management. They are expected in the country shortly.

By Monday morning, authorities had pulled 29 bodies from beneath the debris, according to lawyer Nuwan Bopage, who has worked with local residents to protest against the dump.

Authorities were unsure how many more people could still be trapped, but about 30 were reported missing, Bopage told the Associated Press news agency.

"Residents are very angry and traumatised," Al Jazeera's Minelle Fernandez, reporting from Meetotamulla, said.

"They said this was an absolute disaster waiting to happen."

Authorities vowed over the weekend to shut down the dump, which has absorbed much of Colombo's rubbish over several years amid heavy construction and renovations in the capital.

As the rubbish piled up, it began threatening the nearby homes, prompting residents to stage regular protests while complaining of health hazards.

"These people did not choose to live next to a dump. But they brought the garbage in and made this place horrible," said rickshaw driver Dilip Mirmal, 34, whose home was spared while those surrounding were completely subsumed. He counted 23 of his neighbours among the dead.

"This is a government-made disaster," he told the Associated Press news agency.

"I have a mix of feelings - of anger, frustration and sorrow. We have been trying to protest and raise these issues, but no one was listening."

'The whole area was shaking'

On Monday, soldiers were digging with backhoes and shovels, as relatives of the missing pointed out where their houses once stood amid coconut, mango and banana trees.

Those homes now lay in piles of collapsed concrete walls encased in a wall of mud up to eight metres high and mixed with plastic bags, broken glass and other rubbish.

Bicycles and auto-rickshaws were crushed or lying topsy-turvy.

More than 600 of the area's residents were sheltering in nearby schools, while 11 people were being treated at a hospital for injuries.

One auto-rickshaw driver described a narrow escape. He was returning home with his wife, two sons and daughter when they stepped out from his rickshaw and his daughter said the ground seemed to be moving beneath her feet.

"There was a strong wind from the side of the dump, and my daughter shouted that the mound was splitting," Rasika Sanjeewa, 41, told AP. "Suddenly, one slice of the mound came crashing down. The whole area was shaking."

Debris blocked them from fleeing immediately, but eventually they found a way out, Sanjeewa said.

When they arrived later at their friends' home, where they had planned to celebrate the new year, they found it buried and their friends dead - a mother and daughter who worked as daily wage labourers.

"Many say this could have been prevented if authorities had seen the scale of the disaster," Al Jazeera's Fernandez said.