Banking inquiry chairman Ciarán Lynch has pledged to drive down projected costs of the investigation into the €64 billion bailout ahead of the cross-party committee’s last meeting until autumn.

Committee members were initially advised the cost of an 18-month inquiry into the collapse of Ireland’s banking system would be more than €5 million. The committee will meet on Wednesday and televised sessions with key witnesses are expected to begin next April.

“The issue of cost is one that the inquiry team is very conscious of and it has been dealt with at every meeting to date,” Mr Lynch said. “As we have examined these costs we’ve seen reductions in a number of areas as opposed to what was previously estimated.”

Expenditure estimates for Oireachtas staff salaries, wages and allowances have risen from €23.9 million this year to €26.8 million in 2015, with provision for the costs of the inquiry.

Proposals for fitting out the parliamentary campus for a state-of-the-art investigation accounted for the balance of the suggested bill, along with legal costs and other expenses.

Economist Colm McCarthy is among the members of an expert group working on a pro- bono basis which will present an initial advisory report to the committee on Wednesday.

Also among the group’s members are economist and commentator Megan Greene of Maverick Intelligence and Comptroller and Auditor General Séamus McCarthy.

Mr Lynch, Labour TD for Cork South Central, insisted there would be no “showboating” during public hearings when the committee members will question key witnesses.

Senior figures such as former taoiseach Brian Cowen have already indicated their willingness to attend.

Witness briefings

Mr Lynch said all witnesses would be advised in advance why they were being brought before the committee.

“The questions must at all times be in line with the terms of reference,” Mr Lynch said. “It is critical that they are structured in a coherent and robust manner. That will ensure we don’t have mission drift or mission creep.”

There have already been numerous reports into Ireland’s financial crisis, including those popularly known as Nyberg, Regling-Watson and Honohan. However, Mr Lynch said the inquiry he was chairing would be different in important respects.