INDEPENDENT TD Michael Lowry is under pressure to provide further details about a payment he made to a land agent.
Mr Lowry has maintained that he fully declared the payment of either stg£200,00 or stg£250,000 to Northern Ireland-based land agent Kevin Phelan in his company's annual accounts.
But there are no specific details in the annual accounts filed by Mr Lowry's refrigeration company Garuda of the payment.
A business source said this was not unexpected because company accounts just provided an overall picture of a company's finance – and generally not individual transactions.
But there are questions over whether there is a "contradiction" with evidence Mr Lowry gave to the Moriarty Tribunal.
Mr Lowry said he paid Mr Phelan more than stg£60,000 to ensure he had no future claim to a land project in Wigan he was involved in, according to the tribunal report.
But in the taped conversation with Mr Phelan in 2004, Mr Lowry constantly referred to a sum of either stg£200,00 or stg£250,000, which he said he paid to Mr Phelan.
SF TD Padraig MacLochlainn has called on him to make a "clarifying statement". A spokeswoman for Mr Lowry said he was not available for comment.