Gardai investigating the discovery of explosives in a Dublin apartment believe they were smuggled in as part of an airline security check that went wrong.

A Slovakian man in his 40′s was arrested but has since been released from custody after the high grade commercial explosives were found earlier today.

It’s believed the explosives were planted in the Slovakian man’s luggage as he returned home to Dublin last Saturday after the Christmas break.

100 grams of what’s known as RDX  – enough to detonate a plane – went through the flight undetected.

Authorities at Poprad-Tatry Airport only notified gardai about the security exercise this morning.

Police traced the man, who is in his 40′s, to an apartment in Dorset Street in Dublin’s city centre.

Adjoining properties had to be evacuated as army bomb experts ensured the device was stable.

The Slovakian man in his 40′s was arrested for questioning but has since been released without charge.

A spokesperson for the Department of Foreign Affairs says its awaiting a full report on the incident and if necessary the Department will pursue the matter with the authorities in the country concerned.