It is being claimed today the Sinn Fein TDs are breaking Oireachtas rules by paying activists out of cash claimed for travel expenses.
Prominent frontbenchers have revealed that part of their expenses claims were diverted to pay additional staff.
According today's Irish Independent, unspent travel expenses are supposed to be returned to the Oireachtas under rules introduced in 2010.
The Irish Independent highlights the case of Sinn Fein finance spokesman Pearse Doherty who put €8,000 worth of unspent travel and accommodation expenses towards hiring part-time party workers.
Padraig Mac Lochlainn, also confirmed that he used unspent expenses in the same way.
The revelation is likely to fuel calls for an unprecedented inquiry into how the party uses taxpayer funds.
Despite the admissions, Sinn Fein headquarters last night denied that its TDs were using unspent expenses in this way.
The Irish Independent claims its investigation reveals for the first time how Sinn Fein relentlessly and efficiently uses the political funding system to maximum advantage here, in the North, at Westminster and in the US.