The announcement came after Nisa-Today's failed to piece together a deal to present to its board and 700 members at a board meeting yesterday.
The collapse of the proposed tie-up followed the deal's bankers getting cold feet amid allegations that Nisa-Today's and Costcutter were 'acting like a cartel'.
Following the accusation - which came from a group of Nisa-Today's own independent wholesalers and retailers - Icelandic bank Kaupthing was said to be 'uncertain' over the deal and revised its backing to attach more strings.
A spokeswoman for Nisa-Today's told Retail Week: 'Nothing was presented to board members yesterday, so the merger is now definitely off.'
The merger had been proposed in May in order for the two companies to 'survive' as Tesco and other large retailers moving increasingly into the convenience market.