The future operator of the account was expected to be revealed during the summer, but the announcement has yet to be made.
Conservative business spokesman Jonathan Djanogly told MPs at Commons' question time that the stoppage was causing major distress and uncertainty to subpostmasters.
"Could you explain why the delays continue and when will the announcement be made and certainty given to customers, the Post Office and its staff?" he asked business minister Pat McFadden.
McFadden replied: "When we have made a decision it will be announced in the normal and proper way."
An extra 3,000 post offices face closure if the government does not extend the Royal Mail's POCA contract beyond 2010, the National Federation of Subpostmasters (NFSP) has warned.
NFSP general secretary George Thomson admitted that retaining the contract for POCA2 would not be a "cure-all" for the post office network but would "provide the Post Office with breathing space to deliver the new products and services required to ensure that the new post office network was given the best possible chance to survive and thrive in the future."
Political support for Post Office Ltd winning the contract is strong. Before parliament's summer recess, 250 MPs signed an Early Day Motion calling for the Post Office to continue to operate the successor product.