Excitement over a potential Celtic oil boom spread to Northern Ireland when Providence Resources claimed that a prospect off the coast of county Antrim revealed the existence of more than 500m barrels of hydrocarbons.

Providence has already reinvigorated the search for oil and gas off Ireland with encouraging drilling strikes further south at the Barrywroe field in the Celtic sea.

Shares in the company rose a further 2% to 665p after it told the London Stock Exchange that new geological analysis plus airborne survey data revealed "significant oil potential" in the Rathlin basin.

John O'Sullivan, technical director at Providence, said: "We have now commenced planning for a future drilling programme in 2014."

Oil analysts in London described the announcements as encouraging but warned that more work was needed to confirm whether Northern Ireland could become a serious oil-producing region.

"It looks very promising following on from the finds at Barrywroe but it would be premature to talk of a new oil boom. There is no 3D seismic of the area yet and we will need to wait for new drilling results," said Sam Wahab, equity research analyst at stockbroker Seymour Pierce.

The investment and oil community will in future be watching carefully wells planned by the oil major, ExxonMobil, at the Dunquin oil and gas prospect off County Kerry to start in the next few weeks.

A resurgence of interest in Irish exploration has been partly stimulated by low potential tax rates on any energy produced – 20%, compared to up to 80% in the North Sea.