Thousands of South African former gold miners and their families can pursue a multi-million-dollar class action against mining companies over silicosis contracted at work, a judge in Johannesburg ruled Friday.

"We hold the view that in the context of this case, class action is the only realistic option," Judge Phineas Mojapelo told the High Court in Johannesburg.

"It is the only avenue to realise the right of access to the courts provided by the constitution."