Ireland is planning an external review of its Department of Finance, its debt agency and its statistics office after an accounting error meant the country overstated its national debt by 3.6 billion euros (3.1 billion pounds) since 2010.

Finance Minister Michael Noonan told parliament on Wednesday that officials from the country's National Treasury Management Agency (NTMA) told the Department of Finance about the accounting error in August 2010 but nothing was done about it.

It would seem that the significance of the matter was not appreciated at that time, Noonan said.

The NTMA raised the issue again ahead of the publication of medium-term forecasts on Friday and Noonan said he was informed of the error on Tuesday.

The mistake arose due to a change in how loans from the NTMA to a housing agency were accounted for.

This is a very serious issue and I am determined that the necessary lessons are learned and immediately acted upon, Noonan said. It is clear that there has been a systems failure.

The secretary general of the Department of Finance has already asked for a full report on the matter and will arrange for an external review of the systems in the Department, the NTMA and the Central Statistics Office (CSO) to be carried out.

The Department of Finance has already come in for heavy criticism over its handling of the country's financial crisis.

Germany last week uncovered a 55 billion euro accounting error, leaving the government deflecting ridicule for being inept and hypocritical after its steady criticism of Greek book-keeping practices.

(Reporting by Carmel Crimmins)