A government commission investigating the massacre of 34 striking miners by South African police says the force has lied, withheld documents and apparently doctored other papers.

In a statement issued on Thursday, the Marikana commission also said it had to search computer hard drives of officers to discover documents relating to the 2012 shootings that recalled the worst excesses of South Africa's apartheid era.

The Marikana massacre was the most deadly police action since the end of white minority rule in 1994.

The commission, which was appointed by President Jacob Zuma to investigate the deaths, said documents show the police version of events at the platinum mine "is in material respects not the truth".

The statement said the thousands of pages of new evidence include documents the police had previously said did not exist and material which should have been disclosed earlier by police.

Police acknowledged "over-reacting" at Marikana during an inquiry held in October last year.

In an opening statement to the inquiry, police officials said that "the response of some police officers may have been disproportionate to the danger they faced from the group of more than 200 armed protesters".

The Marikana commission adjourned until Wednesday to study the new evidence.

Source: Al Jazeera and agencies