A new grocery market ombudsman to protect small suppliers and retailers from harmful supermarket buying practices may not start work for another two years.

Retailers have reacted with concern at the "glacial pace" of the implementation of the Grocery Code Adjudicator (GCA) to support the Grocery Supply Code of Practice (GSCOP), which was published last year.

The GCA was recommended by the Competition Commission following its two-year grocery market investigation. When introduced, the new regulator will be charged with investigating abusive practices and arbitrating disputes between supermarkets and suppliers.

Association of Convenience Stores (ACS) chief executive James Lowman said: "The implementation of the grocery code adjudicator has moved at glacial pace. A regulator is needed and until there is one consumers will continue to be at risk from harmful buying practices by the biggest retailers."

A draft Bill is still awaited to allow appointment of the policing role, and a final Bill is not expected to be agreed until 2012, for the GCA to start in mid 2013.