Nisa-Today's is playing it cool following a complaint to the Office of Fair Trading about its trading practices.
The group is understood to have quickly outlined its position to the Office of Fair Trading after five individuals within the Nisa Members Association, a rebel faction within the organisation, lodged the complaint with the regulator last week.
A Nisa-Today's spokeswoman said: "Nisa-Today's strongly denies it has taken part in any cartel activity."
The company is understood to have conducted an internal investigation in order to satisfy itself that there were no grounds for the complaint.
The OFT must decide within a month whether it merits investigation.
Meanwhile, symbol group RedOrange has resigned from the NMA after it announced its complaint to the OFT and other Nisa-Today's members have distanced themselves from the NMA's actions.
In a further statement this week designed to remove uncertainty among members concerning the progress of its proposed merger with Costcutter, Nisa-Today's said due diligence was close to completion.
However, it added that it aimed to issue a circular to all its members outlining final merger proposals by 9 November, ready for a general meeting on 30 November.