JOHANNESBURG – The world's top platinum miners kicked off talks with South Africa's unions on Tuesday in what is expected to be a tough round of wage talks, as a rise in profits is likely to provoke higher wage demands.

The majority union in the platinum sector, the Association of Mineworkers and Construction Union (AMCU), said it had presented its demands to Anglo American Platinum (Amplats) and would do the same to the rest of the firms this week.

"It is important that they look at their employees wages and there is nothing really they can cry foul of, we are hopeful that they will look into lending an offer that is reasonable," said AMCU General Secretary Jimmy Gama.

AMCU has demanded a hike to R17 000 a month, or around 48%, for its members.

Sibanye-Stillwater, which is set to meet the union this week, said the platinum price has remained depressed and that the current demand was not sustainable for the miners.

"There has been decades of under investment in capital and that is why there has been mine closures in the last few years. You cannot pay out everything in higher wages, we need to also invest in the sustainability of the industry if we want to preserve jobs in the long term," said Sibanye spokesperson James Wellsted.

Amplats and Impala Platinum declined to comment on the negotiations.

Africa's most industrialised country has the biggest and most lucrative platinum reserves but a strike in 2014 cost the industry billions and forced firms to cut jobs and shed mines after a supply glut weighed on platinum prices.

Negotiations may be tough, however, as higher prices for palladium and rhodium and a weaker rand currency have boosted profits at miners such as Amplats, Sibanye – now combined with Lonmin – and Implats after several years of losses.

“Amplats will probably be under the most pressure as their earnings and share price have run the most this year of the bunch,” said Peter Major, an analyst and director of mining at Mergence Corporate Solutions.

Amplats last month flagged that its half-year earnings are expected to rise by at least 80%, boosted by the increased metals price.