Police searching the Panamanian-registered "MV Matthew" vessel said more than two tonnes of cocaine with a street value of up to 150 million euros ($158 million) was on board, a source told the Irish Times newspaper.

The 189-metre-long bulk carrier was intercepted Tuesday by police and Irish navy rangers who fired warning shots before boarding and escorting the ship to Cork port where it is currently detained.

Police said Tuesday a "significant quantity" of suspected drugs was found on board, and that three men were arrested.

Irish justice minister Helen McEntee said in a statement that the drugs on board would have "no doubt been destined for Irish and European markets".

"It will represent a blow to the organised-crime gangs involved in drug distribution internationally," she said.

According to the Irish Times, police were tracking the vessel on suspicion it was carrying cocaine from South America and making deliveries of the drug to smaller vessels at sea.

After a fishing trawler ran aground on a sandbank off Ireland's southeastern coast Sunday, police rescued two men from the boat before arresting them on suspicion of organised crime offences.