Opponents to the assessments say more than 1,000 people who had their benefits cut as they were deemed fit work subsequently died last year.
DPAC's Roger Lewis told the BBC the assessments were causing "huge damage and distress to disabled people".
"We now have a situation where we know that people have gone through the Atos assessments who have unfortunately died as a result. Some have committed suicide. Some have had heart attacks."
Last Friday saw a large protest at the Atos's London headquarters, as well as a demonstration at the Department for Work and Pensions, also in the capital.
Both Prime Minister David Cameron and Chancellor of the Exchequer George Osborne have now been loudly booed by crowds at Paralympic events.
Cameron received his negative reception when he was shown on the big screen at the Aquatic Centre, while Osborne was on the end of deafening disapproval at a packed London Olympic Stadium as he was announced to present the medals for the 400m T38.
Not all UK politicians have been booed by Paralympic crowds, with former Labour Prime Minister Gordon Brown receiving a "rather contrasting reaction" as he presented medals at the swimming, the Guardian reported.
It is not clear if the reception for the Conservative MPs is related to the Atos contract, or simply a reflection of the slumping support for the Tory-led Government in the polls.
British paralympians have also spoken out against proposed cuts to the disability living allowance, telling the Guardian that without benefit they would not have been able to participate in society, let alone sport.
"Without DLA I would not have been able to do what I did or be a top athlete," Ade Adepitan, former-Paralympic wheelchair medallist told the paper.
Athletes also hid their security pass lanyards, which bear the Atos logo, during the opening ceremony to the games, however ParalympicsGB rejected this was a protest, rather claimed they had been tucked under their uniforms as it was windy.
- Herald Online