THE head of the Renewable Heat Association has admitted it is possible that some of its members may have abused the botched RHI scheme.
Michael Doran said some of the hundreds of boiler owners it represents, whose identities are protected under a court ruling, could have joined "specifically to hide behind the injunction".
The comments come as the group brings forward a separate legal challenge against the Department for Economy, calling for contracted 20-year payments under the Renewable Heat Incentive scheme to be honoured.
Last month economy minister Simon Hamilton announced proposals to cut the cash-for-ash overspend.
These included imposing a one-year, two-tier tariff structure and payment cap from April 1, with a longer-term plan to follow.
Mr Doran, who also heads up the non-profit group Action Renewables and does not have an RHI boiler, claimed that what the government had done to date is "illegal" and confirmed that legal papers were lodged on Friday.
"People joined this scheme on the understanding it was a 20-year contract and two years into the contract, the government has torn that up," he told The Nolan Show.
"Some of our participants have invested over £100m in the NI economy and they stand to lose a substantial part of that, if the tariffs are reduced."
During the same interview, Mr Doran confirmed that there was no vetting process in place for anyone wishing to join the Renewable Heat Association and conceded there may be members abusing the scheme.
The group saw a spike in applications in the hours before a cut-off point set by a judge for protection under the injunction.
"It is possible that there are some in there who have been acting improperly, who will be found to have been acting improperly. They won't be able to sign up to our code of good practice and we will throw them out," Mr Doran said.
The planned internal 'code of good practice' involves members declaring their RHI subsidies and the nature of their application, but does not involve any form of inspection.
It is to be carried out purely on the basis of "good will" according to Mr Doran.
DUP economy minister Simon Hamilton has said he will be "robustly defending" his RHI cost control proposals in the wake of the fresh legal challenge.
"These regulations are the vital first step in radically reducing the burden of the Renewable Heat Incentive scheme on the Northern Ireland budge," he said.
"The department will be robustly defending its actions in introducing these essential cost saving regulations. I have also made it clear repeatedly that the department will take all necessary steps to counter abuse and potential fraud in relation to the scheme."
When asked whether the minister intended to release names of RHI claimants not covered under injunction, including those who have consented to their identities being revealed, a department spokesman said again that the minister "continues to consider the court judgment and will reflect on options to ensure maximum transparency".
Mr Hamilton had promised to publicly release the names of all non-domestic RHI claimants.
