The British Office of Fair Trading is reportedly considering holding a fresh competition inquiry into the grocery industry.
In August, the regulator backed down from holding a full market review. However, The Times newspaper says this decision is now being questioned.
This follows a group of independent retailers launching a lawsuit against the decision not to ask the Competition Commission to review the dominance of supermarkets.
If a full review is recommended, it is likely to concentrate on Tesco, which controls just over 30% of the UK market.
If the OFT decides a full review is necessary, the commission could put new restraints on supermarkets or force the sale of parts of their business.
The Association of Convenience Stores welcomed the OFT's decision to reconsider a review.