The death toll in a collapsed landfill in the central Philippines has risen to 11, authorities said, as hopes of finding survivors dim.

The landslide occurred at the Binaliw landfill in Cebu City last week while more than 100 workers were on site, officials said.

Rescuers have so far pulled 12 injured people out of the debris, but more than 20 people still remain missing. One local fire official had earlier told AFP that it was unlikely for people to still be alive three days after tons of debris and trash had collapsed over them.

The incident has sparked calls for an investigation into the cause of the collapse, as well as a review of the country's waste management system.

Environment authorities have since ordered Prime Integrated Waste Solutions, Inc., the landfill's operator, to suspend its activities at the site.

The company would have to submit a compliance plan within 90 days, the local Department of Environment and Natural Resources said in a statement on Monday.

The department also said it would conduct an investigation into the cause of the collapse and hold accountable the parties responsible.

Lawmakers have called for reviews of the country's waste management system and working conditions of waste workers.

This should have never happened, Senator Imee Marcos, who has requested an investigation into the Binaliw landfill's operations, said on Monday. We have seen similar tragedies before, yet the same dangers persist.

The lives lost in Cebu demand clear answers and real reforms.

Bienvinido Ranido, who lives near the landfill and whose wife worked there, told Reuters that he saw people fleeing from the site last week, saying the garbage exploded.

I quickly took my motorcycle and rushed to the landfill. When I got there, I saw the collapsed building and it was buried by the garbage. I just screamed, he said. Rescuers retrieved his wife's body the next day.

The Binaliw landfill covers an area of about 15 hectares (37 acres).

While authorities are still looking into the cause of the landslide, a preliminary report from the local Mines and Geosciences Bureau points to continuous rainfall in recent weeks, which made the rubbish heavier, as well as other engineering factors, local media reported.

Landfills are common in major Philippine cities like Cebu, which is the trading centre and transportation gateway of the Visayas, the archipelago nation's central islands.