The biggest union in South Africa's platinum sector has called a strike over pay, the biggest in the sector since the 2012 Marikana massacre.

On that occasion 34 protesting miners taking part in an illegal wage protest were gunned down by police.

Thursday's strike over pay will halt production by the world's top three platinum producers.

A separate strike in the gold sector also planned for Thursday has been postponed following a court ruling.

Judge Hamilton Cele said that a decision on whether the protest by the Association of Mineworkers and Construction Union (Amcu) is "protected" - enabling workers to down tools without being dismissed or disciplined - will be taken on 30 January.

Militant

However Amcu officials say that that 70,000 of its members in the platinum sector will strike indefinitely.

The BBC's Milton Nkosi in Johannesburg says that the militant union is demanding a "living wage" - of about 12,500 rand ($1,200; £690) - more than double their current pay.

Our correspondent says that most of those workers taking part in the strike work deep underground as rock drill operators.

Unlike the Marikana strike, the walkout by the platinum workers is legal.

All three companies - Anglo American, Impala and Lonmin Platinum - have confirmed receiving official notices of strike action by Amcu.

The mining companies insist that they cannot afford the pay increases because of high production costs and low demand.

Amcu replaced the National Union of Mineworkers (Num) as the biggest union in the platinum sector during the Marikana protests.

Mineworkers criticised the Num, which is affiliated to the governing African National Congress, of being too friendly with business.

As President Jacob Zuma and the ANC prepare for elections in April, he can ill afford the negative publicity a strike would bring, correspondents say.

The party was sharply criticised for not doing enough to prevent the Marikana massacre.

South Africa holds about 80% of the world's known platinum reserves and is the fourth-biggest gold exporter.