The union said no wage talks are scheduled, and that the strike will continue with no new mandate from workers.
Amcu said the platinum 'cabal' has failed in its attempt to sell its offer to workers.
Only an "honourable settlement" can resolve the three-month long strike in the platinum sector, the union said.
"We call on the platinum cabal to be patriotic. Only an honourable settlement can resolve the strike," union leader Joseph Mathunjwa told reporters in Johannesburg.
"Our members have rejected the offer. The Amcu strike is protected. No one should put pressure on us... We appeal to progressive forces to put pressure on the employer to accept this demand."
Amcu members at Lonmin [LON], Impala [JSE:IMP] and Anglo American Platinum operations in Rustenburg, North West and Northam in Limpopo downed tools on January 23 demanding a basic salary of R12 500 over a period of four years.
Mathunjwa said the R12 500 demand was based on the escalating of cost of living and the "slave-structured" wage grades in the mining sector.
He said the R4 500 wage in the mines was earned by Indian and white mine employees in 1987.
"There is no good story for mineworkers since the dawn of democracy."
The strike has hit 40% of global production of the precious metal.
The three companies took their latest wage offer directly to the roughly 70 000 striking miners after wage talks with the union collapsed. The firms said many of the strikers had expressed a desire to return to work.