During an opposition day debate in the House of Commons, she said: "We want the Government to act swiftly on the grocery ombudsman.
"That will lead to less pressure on suppliers and an end to unfair competition, and greater price transparency in the supermarket sector," she added.
Creagh called on the Government to bring forward proposals for the groceries code adjudicator early in the next Parliament "to ensure fairness across the food supply chain".
In response, Defra minister Caroline Spelman insisted that the Government was committed to introducing the adjudicator "as soon as possible".
She denied that the adjudicator would have the effect of increasing supermarket prices.
Meanwhile, the NFU has revealed that establishing an adjudicator will be one of its main priorities for the year ahead.
The NFU horticulture and potatoes board "will lobby for meaningful progress to be made this year on the establishment of a Groceries Supply Code of Practice adjudicator and in particular for the inclusion of third-party evidence in the draft bill", according to its Top 10 Policy Priorities 2012 document.