The economics expert heading the inquiry into the near collapse of the Irish banking sector has yet to interview senior executives at the main financial institutions.

Klaus Regling and his co-investigator Max Watson have not spoken to senior executives at the two main banks, AIB and Bank of Ireland. It is also understood that no board member or senior executive at Irish Nationwide Building Society, one of the worst affected institutions, has been contacted by the inquiry either.

The investigation by the former International Monetary Fund executive is due to wrap up this week.

The findings by the German, who began the probe in February, will form the basis for a wider commission of inquiry that will begin its work in June. It is understood, however, that Regling has held meetings with Anglo Irish Bank executives, including the new chief financial officer Maarten van Eden.

A spokesman for the Department of Finance confirmed that several of its officials have met with Regling. Kevin Cardiff, the secretary-general at the department and the former head of its banking division, told a Dáil committee earlier this month that he has discussed the banking crisis with Regling.

In his letter appointing Regling, finance minister Brian Lenihan said while the inquiry should look at how the global financial crisis affected Ireland, "a central element of the report is to identify factors specifically pertaining to the Irish banking system which exacerbated the impact of the international financial crisis for Ireland.

"I would also ask that you highlight in your report the areas in relation to the conduct, management and corporate governance of indiv- idual institutions that you consider necessary for subsequent investigation by the statutory Commission of Investigation," Lenihan wrote. The department said the report will be considered by the government before it is published. A publication date has not yet been set. Minister Lenihan has said the commission of investigation will issue its final report by the end of the year.

The Regling inquiry did not respond to a request for comment. Regling told a Dáil committee in February that while he would not name individuals in his report, he would list institutions that contributed to the crisis.

The Central Bank governor Patrick Honohan is carrying out a separate report on the response of the bank and the Financial Regulator to the meltdown. A spokeswoman for the governor said he will meet his deadline and submit the report at the end of May.