Johannesburg - Platinum union Amcu has made new and “unaffordable” demands beyond an 'in principle' deal struck with producers last week, the companies said on Wednesday, dashing hopes of an end to a five-month strike, the worst in South African history.

The Association of Mineworkers and Construction Union (Amcu) last week put the broad pay offer to its members.

While the striking miners urged union leaders to accept the salary increases offered, they voiced concerns about the time frame of the agreement and other benefits such as housing allowances.

“The response (from the union) contains new material outside the principle agreement,” Anglo American Platinum spokeswoman Mpumi Sithole said.

Impala Platinum said the additional demands included a 3,000 rand “come-back bonus” and a moratorium on all restructuring and retrenchments.

“We don't know if the mines are going to make money one or two years from now. How do we agree not to restructure? It's something that we could never agree to,” Implats spokesman Johan Theron said.

Amplats and Implats said they could not afford to meet the union's extra demands.

Amcu leaders could not be reached for a comment.

Amplats was expected to meet Amcu later on Wednesday, Sithole said.

About 70,000 members of the hardline union downed tools in January at Amplats, Implats and Lonmin, hitting 40 percent of global production of the metal used for emissions-capping catalytic converters in cars and dragging Africa's most advanced economy to towards recession. - Reuters