Gardaí from the Bureau of Fraud Investigation have begun a number of searches at the offices of Anglo Irish Bank in Dublin.
The officers are working with the Office of the Director of Corporate Enforcement (ODCE), which is investigating a series of financial scandals related to the bank.
A Garda spokesman said that a search warrant had been issued yesterday by a judge in the Dublin District Court.and was executed this morning.
Up to 20 officers working under the ODCE are involved in the search.
The gardaí are understood to be searching the St Stephen’s Green offices for books, documents and other materials that could provide evidence of any offences under company law.
Anglo Irish Bank was nationalised last month after the share price plummeted amid a wave of controversies, including a loans-for-shares scandal, revelations about secret loans to former chairman Sean FitzPatrick and a multibillion-euro deposit from an apparent rival bank to boost its books.
Minister for Justice Dermot Ahern is being kept up to date on developments in the Anglo investigation.
Mr Ahern said he would ensure the ODCE had sufficient staff and resources to carry out its work.
“Legislation is in place to bring to justice those who may have played hard and fast with the financial security of this country,” he said.
He added: “We operate the rule of law. As far as I am concerned, that provides that, whether you have a balaclava, a sawn-off shotgun or a white collar and designer suit, the same rules apply.”
Taoiseach Brian Cowen told the Dáil this afternoon that the investigation at Anglo Irish Bank was a matter for the "requisite authorities".
“The Government does not intervene in such investigations," he said.
During leaders' questions, Mr Cowen told Fine Gael leader Enda Kenny he had "consistently made clear" that the proper authorities were investigating what occurred at Anglo Irish Bank.
He said he did not want to say anything that would prejudice any possible future civil or criminal actions.
Mr Kenny said the latest development was "another hammer-blow to the creditworthiness of Ireland Inc." He called on the Government to take action to restore the confidence of the markets in the creditworthiness of the State.
"You…are in a position to rectify this problem, before someone else rectifies us for us," Mr Kenny said.