Democratic Alliance leader Mmusi Maimane is calling on President Cyril Ramaphosa to declare August 16 a Marikana Memorial Day, to be commemorated every year.
August 16 will mark the sixth anniversary of the Marikana tragedy, where 34 mineworkers were shot and killed by members of the South African Police Service.
"The President is empowered, through proclamation, to declare any day to be observed and commemorated and I implore him to do the right thing and declare tomorrow a commemorative day," Maimane said in a statement on Wednesday.
He said he hoped Ramaphosa would accede to the request in honour of those who died.
"This need not be a difficult decision for an administration that has posited itself as a 'New Dawn'," he added.
Ramaphosa's spokesperson Khusela Diko said on Wednesday that they were not aware of the request.
Maimane believed the declaration was in the interests of justice and national unity. He added that it would give meaning to Ramaphosa's commitment during his State of the Nation Address.
"Healing wounds means more than last month's R100m settlement offer by the ANC government to families of the victims for general damages. Closure cannot be bought," he said.
Maimane said declaring the day a memorial is something Ramaphosa "can and ought" to do to honour the lives who died in the tragedy.
"The Marikana tragedy will forever be a stain on our national conscience and many in society, including trade unions and political parties, believe that tomorrow should be honoured accordingly," he said.
Last year Maimane had also written to then-president Jacob Zuma with the same request.