The final report by the Oireachtas banking inquiry is facing a delay of up to six weeks and is unlikely to be completed until early 2016.

The delay makes an early election unlikely because a final report would have to be agreed before the Dáil – and the inquiry committee – can be dissolved. The report was due to be completed by November 30th. The main cause of the delay is allegations by a whistleblower who worked with the committee.

Senior counsel Senan Allen is investigating allegations that certain witnesses were blocked from attending the committee and claims that preferential treatment was given to some witnesses.

Fianna Fáil Senator Marc MacSharry said the committee was committed to getting its work finished. "The members of the inquiry have a number of commitments, including constituency work [and] legislative duties; and the looming general election is a factor. But if extra time and resources are required to complete this work than so be it."

The committee agreed to spend August examining possible conflicts of evidence by witnesses. It will then seek to clarify those by September.

Members have confirmed the witness list is now closed.

Public hearings

There are two weeks of public hearings inSeptember before the drafting of a report can begin. Those referenced by the committee will have an opportunity to read the draft before a final report can be agreed.

Inquiry chairman Ciarán Lynch is to seek an extension in the Dáil in September but is said to be reluctant to ask for more than one.

Meanwhile, Fianna Fáil and Sinn Féin have demanded an urgent response from Minister for Finance Michael Noonan about claims made before the inquiry.

Former Irish Bank Resolution Corporation chief executive Mike Aynsley claimed a senior official in the Department of Finance had asked the bank to take a lower price for a business. He said the bank was told not to take the higher bid because it was made from "a named Irish businessperson or his company".

Mr Aynsley said the official claimed he had the backing of Mr Noonan. Sinn Féin deputy leader Mary Lou McDonald and Fianna Fáil TD Dara Calleary separately called for an “urgent response”.

A spokeswoman for the department said neither the department nor the Minister would be responding.

Former chairman of Anglo Irish Bank Alan Dukes said he did not believe Mr Noonan was aware of the comments made by one of the department staff.

“I don’t think that’s true. I find it hard to believe that he [the Minister] would say that,” he said. Mr Dukes declined to reveal the identity of the businessman mentioned.

When contacted, Mr Aynsley also declined to comment but said he hoped the commission of investigation into transactions by IBRC would examine this.

Former secretary general of the Department of Finance John Moran said it would be inappropriate for him to comment.

However, he said he was advised by the inquiry’s legal team not to reference any issues that might spill into the commission of investigation’s terms and questioned whether Mr Aynsley had been given the same advice.