Additional security procedures are to be imposed on aircraft departing Dublin Airport and arriving into other EU airports.

This follows an audit by the European Commission on the airport's compliance with EU aviation security rules.

Speaking on RTÉ’s Morning Ireland, Minister for Transport Leo Varadkar said aircraft searches, which were suspended 18 months ago, are to be re-introduced.

Passengers transferring through another European airport will have to be re-screened when they land at those airports from Dublin.

Although this does happen at times, it will now be the norm all of the time. The Minister said aviation security had to be "100%".

Minister Varadkar said the move does not impact on other airports in the State.

He visited the airport yesterday after meeting officials from the Dublin Airport Authority.

"The first matter has been resolved. The other is technical in nature and does not affect passenger screening or baggage handling at the airport.

"Dublin Airport will adopt back-up procedures to address this second matter in the short term, while a longer term solution is implemented, and the security of the airport is maintained."

The DAA said the audits are carried out on a regular basis and it is working with the Department of Transport to resolve the issues.

A spokeswoman for the European Commission said the imposition of additional security procedures at airports was not usual.

She said the Commission had flagged the problem with Dublin Airport but it had failed to remedy it quickly enough and the Commission now wanted to see the issues resolved as soon as possible.

Aer Lingus said it is concerned about the inconvenience that may be caused to its customers as a result of changes to security measures.

However, the airline says it will work closely with the relevant authorities to minimise that inconvenience and called on the Department of Transport and the DAA to resolve the issues as a matter of urgency.

It said in the meantime there will be no changes to check-in procedures or flights times as a result of the changes.

Meanwhile, the Department of Transport has denied a claim by Ryanair that the security breach was at the highest possible level.

The airline said it is not aware of the exact details and is due to received a briefing on the situation tomorrow.

Speaking on RTÉ's News at One, Ryanair's Chief Financial Officer Howard Miller said: "The material level of this breach is so high that they've had to publish it, and we now await what other airports in other countries and other aviation security authorities will do".

The Department said there had been no security breach, but two "deficiencies" that were picked up during an audit.

It said one of the matters will be resolved today, and the other relates to a new regulation and back-up measures are in place to address this.

The Department insisted that neither matter relates to the screening of ordinary passengers or luggage.

Earlier, Ryanair called the Government to confirm that airlines and passengers will be compensated by the DAA and the Department of Transport for any additional costs or delays as a result of the changes.