Teagasc, the agriculture and food development authority, said the current dry weather is "playing havoc" with potato growers.
Its final crop report for this year said all soils are showing large soil moisture deficit and growers with irrigation facilities were struggling to apply enough water to replace the moisture loss.
"Yields of potatoes, especially late sown, which are not irrigated will be lower than normal as a result of the current drought. Yields of the second earlies are back somewhat and the drought will keep the crop from bulking up as normal. Prices remain buoyant so far," it said.
Kevin Leddy of the Irish Farmers Association said yields of early potatoes had been down by over 50 per cent in places this year.
"Farmers who had expected to get 10 to 12 tonnes per acre have found that they are getting only five and six tonnes because of the dry spell," he said.
As a result, Mr Leddy said, Irish new potatoes were scarce and the farm-gate price being paid to farmers was up €200 per tonne.
"In the main growing areas, there has only been 10 to 12 millimetres of rain so far, but the moisture deficit in growing soils would require three or four times that amount to bring on normal yields," he said.