A group representing the renewable energy industry has made a formal complaint over a report by Northern Ireland's public spending watchdog.
Last month the Northern Ireland Audit Office (NIAO) claimed owners of some renewable technologies were being paid overly generous subsidies from electricity bills.
Auditors said the payments to single wind turbines and anaerobic digester plants, under the Northern Ireland Renewable Obligation (NIRO), were "excessive".
However, RenewableNI, which represents the renewable electricity industry here, has lodged a formal complaint.
It said the report was not fit for purpose - a claim strongly denied by NIAO - and has commissioned an accountancy firm to produce an independent audit and report.
Steven Agnew, a former Green party leader who is now head of RenewableNI, said: "The Northern Ireland Audit Office report into the renewable support scheme is unfit for purpose and should be disregarded."
The NIRO scheme provided subsidies to encourage investment in renewable generation, but closed to onshore wind in 2016 and other technologies the following year.
Auditors found the rate of return from wind turbines was running at over 20% for some, with applicants receiving a payback in just four years.
The report cited one turbine, accredited with the scheme since 2010, which could receive around £95,000 a year in subsidies.
Mr Agnew added: "RenewableNI has learned in response to our complaint, that the NIAO based its report on a single wind turbine project, which is not connected to the electricity grid - an astounding revelation given there are 1,209 single wind turbine generating stations locally.
"RenewableNI members, who have been involved in the development of over 500 small-scale wind projects, do not recognise the cost assumption figures used in the report which fall far short of projects actually delivered."
Mr Agnew said the report had "undermined the significant contribution of the small scale renewables sector to the economy and the environment."
A spokesperson for the Audit Office said: "We confirm that we have received correspondence from RenewableNI and have responded to it. We have also offered to have a meeting with them to discuss their concerns.
"We strongly refute the suggestion that any of the commentary in our report is not fit for purpose.
"In the part of the report referred to by RenewableNI, the absence of official figures from the Department or the Regulator on rates of return for small scale turbines meant that we calculated our own estimated rate of return based on available cost information and the actual average amount of electricity generated by turbines of this size.
"We consider that our calculations are a reasonable estimate of an average rate of return.
"The section referred to by RenewableNI represents only a small part of our overall report.
"As with all of our reports, this report was evidentially based and its factual accuracy was agreed with the Department for Economy and the Utility Regulator in advance of publication."