A hoard of 17th century gold coins goes on display at The National Museum after their discovery in Carrick-on-Suir in Tipperary

Five builders awaiting a reward for handing over a 17th century gold coin hoard have been praised for doing the right thing.

The Carrick-on-Suir guineas - a collection of 81 coins dug up from the grounds of a derelict pub - have gone on show in the National Museum.

Builders David Kiersey, Shane Comerford, Tom Kennedy, Shane Murray and Patrick McGrath found them during ground works at Cooney's bar in the town's Main Street in January.

Ned Kelly, keeper of antiquities at the National Museum, said a finders' reward - an undisclosed percentage of the hoard's value - was being finalised.

"I understand it will be paid very, very shortly," he said. "There's a bureaucratic process. I've seen reports of 500,000 euro but the hoard is not worth anything of that sort, but it is valuable. The guineas are very good quality. They are 91% gold."

It is believed a Catholic merchant must have been saving and storing the coins over several decades in around the time of Oliver Cromwell's campaign in Ireland and the penal laws.

The coins, known as guineas as the gold originated in Guinea, west Africa, date from the reigns of Charles II (1660-85), James II (1685-8), William and Mary (1688-94) and William of Orange (1694-1702). There are 77 guinea and four half guinea coins.

Coin experts from the Spink auction house in London have published a book of coin estimates in which a 1691 William and Mary single Guinea in "extremely fine" condition is valued in the region of £8,000 (9,300 euro). If the coins were all as valuable as this one the hoard would be topping 700,000 euro.

Jimmy Deenihan, Minister for Arts, Heritage and the Gaeltacht, thanked each of the finders, and acknowledged their honesty in declaring the discovery.

"The finders of this important hoard did absolutely the right thing by calling the National Museum," he said. "On discovery of this treasure their immediate instinct was to ensure this collection could be saved for viewing by the people and for future generations, and they are to be thanked and acknowledged for this."