The British Retail Consortium (BRC) has criticised an executive proposal to impose a tax on large retailers.
The proposal was outlined in the NI Executive budget statement, released in March.
Details of the tax are still unknown, but it is understood that it aims to relieve small retailers and provide funding to support town centres.
The BRC said that the "contradictory" proposals should support, rather than penalise the retail sector.
The BRC's Manifesto for Retail in Northern Ireland was released on Friday.
It claimed that rather than providing extra funds for the executive, the proposed levy endangered "bigger economic gains that would come from retail growth and job creation."