Retail experts fear a third supermarket in Castle Douglas would force existing traders out of business.
And they believe a discount retailer such as Aldi or Lidl would also put “severe pressure” on the existing Co-op.
The claims come amidst attempts to remove planning conditions restricting what can be sold from the Cotton Street site currently occupied by Wilko.
At present, only 10 per cent of the floor space can be used to sell food but owners Heptagon want that increased to 80 per cent.
They claim that “reflects the potential market demand within Castle Douglas which is focused on the discount retail sector (eg Aldi/Lidl)”.
And they have asked the Scottish Government to step in on their application as the council failed to make a decision within the allotted time frame.
Documents lodged by their consultants, Progress Planning Consultancy Ltd, say their lease with Wilko is “under review” and while it may be renewed, Heptagon “wishes to secure maximum flexibility in terms of future retail uses, in the event that they need to find a new occupier for the property”.
The firm has claimed that as the existing Tesco and Co-op stores would be the main competitors to Aldi or Lidl, a third supermarket “would not have a significant impact upon the future performance of retailers within the town centre”.
But retail consultants Roderick MacLean Associates Ltd disagree.
They were brought in by the council to review the planning and retail statement prepared by Progress earlier this year.
They claim that the proposed discount foodstore, if approved and developed, would not dislodge Tesco but would put severe pressure on the Co-op and some town centre shops”.
And they also fear that while there may be benefits by allowing a discount food store into the town, these would be “cancelled by reductions in the existing good retail offer”.
In conclusion, they say: “While the current expenditure supports two main supermarkets, there is insufficient convenience expenditure to support three. Closures would most likely occur.”
Progress have until October 7 to lodge a response, with the Scottish Government having set a target date of December 7 for a decision.