Head of Customs Drug Law Enforcement says the style of the device is "nothing new"
Revenue officers have seized cocaine worth more than €5m following a local tip-off in Clare.
The drugs were discovered when a member of the public alerted customs officers to a suspicious "torpedo type" device on the on the beach in the seaside town of Liscannor yesterday.
Authorities believe the device may have been attached below the waterline of a cargo ship "or other maritime vessel".
The device was found to contain approximately 75kg of cocaine.
It is still unclear where the drugs originated or where they were destined for.
Liam Peakin, Head of Customs Drug Law Enforcement said the torpedo style device is nothing new:
Revenue was alerted through the 'Customs Drugs Watch' programme which encourages people living in coastal communities to report anything unusual or suspicious.
Authorities have asked the public not to endanger themselves by "approaching or interfering with suspicious items such as this".
Customs Drug Watch can be contacted through the Freephone line 1800 295295.