Multiples in the Irish grocery market are raking in up to three times the profits they make elsewhere, according to a report by a parliamentary committee.

The report, which has the support of members from both government and opposition parties, also accuses the major retailers of using their market power to impose unfair conditions on suppliers. Demands for 'hello money' and other secret payments were "common practice", it claimed, with suppliers frequently asked for payments and services "considered to be outside acceptable business practice".

The report follows a lengthy investigation by the all-party committee into complaints by suppliers and producers that they had been subjected to unfair demands by major retailers to help fund an ongoing price war. Some retailers have already appeared before the committee and are expected to be invited back to answer further questions and discuss the findings.

As part of the investigation, the committee sought direct evidence from 50 suppliers. However, according to committee chairman Willie Penrose, several declined to co-operate, despite assurances of anonymity, "fearing negative publicity and retribution". Those who did participate claimed Ireland was regarded as "a massive profit centre" for retailers, who had an "insatiable appetite" for margin and who see Irish consumers as "an ideal opportunity to make superlative profits".

One supplier told the committee that the retail margin on his product was 32%-35% in the UK, but 40%-50% in the Republic.

In its report, the committee recommended that the profit margins of both retailers and suppliers be made public. It also backed the government proposal for a statutory code of practice for the sector "to ensure transparency, fairness and equality".

Neither the multiples nor Retail Ireland, their representative body, commented on the findings. They will be invited to respond officially to the report in the coming weeks.