South Africa's Association of Mineworkers and Construction Union (AMCU) has said that its striking members have rejected the latest wage offer from the world's three biggest platinum mining companies.

The three companies took their latest wage offer directly to the roughly 70,000 striking miners after wage talks with the union collapsed.

The strike has been running for nearly four months at Anglo American Platinum, Lonmin and Impala Platinum and has hit 40 percent of global production of the precious metal.

The companies said many of the strikers had expressed a desire to return to work, according to the Reuters news agency.

The platinum producers are offering increases of up to 10 percent and other benefits that they say would raise the overall minimum pay package to $1,200 a month by July 2017.

AMCU had initially demanded an immediate increase to $1,200, but softened that stance in March to staggered increases that would amount to $1,200 rand within three or four years.

"There are no talks scheduled," AMCU President Joseph Mathunjwa told a news conference.

The union would call an industry-wide work stoppage should Anglo American Platinum, the biggest producer, close shafts because of the strike, he added.

Employees have lost more than $698m in wages so far, according to an industry website that provides a running tally.

Companies are staring at revenue losses of more than $1.5bn.