OUR heritage is being "plundered by people for profit", the keeper of Ireland's national treasures has warned.
Ned Kelly, keeper of Irish antiquities with the National Museum, said no site was safe after a hoard of almost 900 historical items was recovered from a looter with a metal detector.
There has been a rise in people illegally using equipment to trawl historical locations for archaeological finds, with some then offered up for sale on the internet.
The massive haul, which was handed over to the National Museum of Ireland, was discovered following a tip-off from the British Museum that an important hoard of medieval silver coins from Ireland had been exported illegally.
It was discovered that a now-deceased British national had been trawling historical sites with a metal detector in Co Tipperary, where he had been living.
"These people can be quite determined in their activities. In recent times, we followed up on reports of treasure hunters operating in the dark with night sights," Mr Kelly said.
In this instance, the 'treasure hunter' had been operating in the Tipperary locality for a number of years.
Before his death, a hoard of 28 medieval hammered silver coins covering the reigns of Edward I and III and dating from 1272 until 1377, were exported to the UK, leading to the tip-off after an image of the coins was uploaded on a website.
Officers from the Norfolk Constabulary also recovered 'gun money', which were coins used as emergency war money by James II, as well as a flat copper axe dating to the early Bronze Age.
A further 29 medieval silver coins were recovered by gardai, along with around 325 metal buttons dating from the 17th to the 19th centuries, some from military uniforms including a button which was inscribed 'County Tipperary Gaol'.
Similar items exchange hands over the internet for between hundreds and thousands of euro, Mr Kelly added.
Mr Kelly said authorities in the UK were still speaking with the man's associate to find out where the items may have been dug up from.
The penalties under the National Monuments Act illegally plundering artefacts include jail terms of up to four years and a €63,500 fine.