Rio de Janeiro: Brazilian mining giant Vale says that communities in the south-eastern state of Minas Gerais have been ordered to evacuate after independent auditors found that one of its dams could collapse at any moment.

On Friday, the company raised the level of risk at a mining waste dam in the city of Barao de Cocais to three, the highest grade. According to Brazil's mining and energy secretary, level three means that "a rupture is imminent or already happening".

Residents in a 10-kilometre perimeter of the dam had already been told to leave by state authorities in February after Vale raised risk levels to grade two, a company spokesperson told the Associated Press on Saturday.

The aftermath days after a dam collapse in Brumadinho, Brazil, in which about 300 people died in January. Credit:AP

The Vale spokesperson, who asked not to be identified in line with company policy, said 442 people had been relocated in temporary housing or with family members since February.