A recently resigned Fine Gael county councillor has accused RTE of trying to "character assassinate" him ahead of an undercover documentary due to be aired next week.
It can also be revealed several politicians have admitted failing to fully declare their interests.
The councillors failed to comply with ethics legislation which requires them to disclose a range of property interests, shareholdings and directorships.
Among those who failed to declare interests is Monaghan County Councillor Hugh McElvaney, who also confirmed he will feature in an RTE Investigates programme which will show him appear to ask for personal reward to carry out work as a public representative.
Mr McElvaney is heard in an advertisement for the documentary asking an undercover reporter "what can you do for me?"
Last night, the councillor claimed he knew he was being filmed and insisted he was "playing along" with the undercover reporter.
He said the reporter posed as a woman representing a UK company seeking to construct wind turbines in his constituency and asked him if he could help obtain planning permission.
He claimed it is a "coincidence" that he resigned from Fine Gael after he was contacted by RTE about the undercover sting. He denied any wrongdoing and claimed his character was being assassinated.
In a statement, RTE said it was satisfied it had acted fully in the public interest.
Mr McElvaney said some of the land he forgot to declare with the council is leased for a "nominal fee" to a local church.
The Irish Independent has established at least six councillors have submitted amended declarations of interests in the past fortnight after omitting relevant details.
Another Monaghan councillor, Fianna Fail's Robbie Gallagher, submitted an amended declaration last week.
The estate agent did not return a call seeking comment, but a letter submitted to the council on his behalf indicates he did not declare a directorship of a financial services company.
This was due to the fact he was no longer involved with the company. The letter said an oversight by an accountancy firm meant "he was not resigned from the company".
Two Cavan councillors also admitted failing to fully disclose their interests.
Fine Gael's Val Smith omitted details of rental properties he owns, while Fianna Fail's Fergal Curtin did not disclose his ownership of rental properties, his job with a timber firm or his involvement with three companies. Both submitted amended declarations last week.
Cllr Smith said he deeply regretted the oversight and said there were no outstanding statutory liabilities on any property he owns.
Cllr Curtin said he had thought he had completed his annual declaration correctly and accurately, but now accepted he hadn't. He said there were no outstanding statutory charges on his properties.
"This was an error on my part and I am happy to correct the record," he said.
Waterford councillor James Tobin told the Irish Independent he had omitted 28 acres of agricultural land and a betting shop from his declaration.
"I genuinely made a mistake. I thought I only had to declare development land," he said.
The Fianna Fail councillor added that he had since made a correct declaration.
Another Fianna Fail councillor, Limerick's Kevin Sheahan, admitted failing to submit an declaration at all. He finally supplied one nine months late.