Tom Greatrex, Labour MP for Rutherglen and Hamilton West, who has campaigned for reform of the assessment, said mistakes could simply be repeated, without the same scrutiny.
The warning comes after Atos announced it was quitting its lucrative UK Government contract early, in 2015.
It also announced it would transfer its infrastructure and employees to its successor supplier "to ensure consistency of service".
Mr Greatrex said: "Mike Penning seems content to re-tender for the same contract without addressing the flaws in the process."
Mr Penning, minister for disabled people, said he was "pleased to confirm that Atos will not receive a single penny of compensation from the taxpayer for the early termination of their contract, quite the contrary, Atos has made a substantial financial settlement to the department."