Brazil’s government has announced it will sue BHP Billiton and Vale for $US5.2 billion after the deadly collapse of a dam at the iron ore mine jointed owned by the companies spilled an estimated 60 million cubic meters of mud and mine waste on November 5.

Environment minister Izabella Teixeira said a lawsuit would be filed demanding that the companies and the mine operator Samarco, which they co-own, create a fund of 20 billion reais to pay for environmental recovery and compensation for victims, The Guardian reported. 

“There was a huge impact from an environmental point of view,” Teixeira said at a press conference in the capital Brasilia.

“It is not a natural disaster. It is a disaster prompted by economic activity, but of a magnitude equivalent to those disasters created by forces of nature.”

BHP and Vale said they would set up a non-profit fund to help authorities clean up the area and affected rivers.

The death toll from the accident rose to 13 people and six people were missing after two waste dams burst and flooded surrounding communities in Minas Gerais, Brazil

It said emergency services in Brazil continued to search for the missing people and operations at the Samarco mine remain suspended.

Samarco joined BHP Billiton in disputing a United Nations' report, which found the waste material that flooded surrounding communities and the Rio Doce river system was toxic. ABC News Australia reported. 

That was despite Vale saying that toxic materials including arsenic were found in the Rio Doce river system after the dams burst on November 5.

Vania Somavilla, Vale's head of sustainability, said a report by the Institute for Water Management in Minas Gerais, found levels of arsenic above legal limits just days after the disaster.

BHP said Samarco had reported that sediment tests carried out by Brazil's geological service (CPRM) from November 14-18 found the concentration of metals in the river system did not significantly differ from tests carried out by the service in 2010.

"Samarco reports that analysis by SGS Geosol, a company specializing in environmental geochemistry, has confirmed that the tailings are composed of materials that are not hazardous to human health, based on the hazard classification of the material under Brazilian standards," the BHP statement said.

It added that a large number of fish died because of a lack of oxygen on account of the high volume of sand and clay tailings material in the waste water.

It said the tailings plume had reached the Atlantic Ocean, around 500 km away, and was dispersing.