The Standards in Public Office Commission will this evening decide whether to begin a full investigation into the Minister for Transport and official contracts secured by his associate Ms Monica Leech.
The State's ethics watchdog is scheduled to meet at 5.30 p.m. to consider the case.
The Commission deferred a decision on the matter earlier this month to seek legal advice in relation to Ms Leech's contracts with the Department of the Environment and the Office of Public Works.
Ms Leech was hired to provide communications advice at a rate of €650 to €800 per day, when Mr Cullen became the Minister for Environment in 2002.
The Government last week said it had ended its working relationship with Ms Leech who has received more than €300,000 for her work.