Jonathan Reynolds, chair of Christians on the Left and a member of the Business Select Committee, told Premier's News Hour it was "a good start" but warned there was more to do.
He said allegations that the company's staff were subject to "Victorian" working practices and lived in constant fear of losing their job or facing disciplinary action for "excessive" talking or spending too long in the toilet were "not acceptable".
A report carried out by professional services firm RPC found "serious shortcomings" at the company's warehouse in Shirebrook, Derbyshire, which Sports Direct's board "deeply regrets and apologises for".
The retailer will now offer its directly-employed casual employees the option of either a zero-hours contract or a permanent contract with at least 12 guaranteed hours a week.
However, it added that agency workers, who make up the bulk of employees at Shirebrook, will not be eligible for the new terms.
Sports Direct will also suspend its controversial "six strikes and you're out" disciplinary procedure.
Mr Reynolds said staff hadn't asked for much: "Decent terms and conditions, the certainty of which you can build a life around.
"To know you're going to get holiday time in the year, to make sure if you're sick or if you're ill you're going to be able to go back to your job and not be discriminated against.
"These are the building blocks of a civilised society."
He warned that parliament and the media would be watching the company to ensure the changes were made.
