DUBLIN (Reuters) - House prices in Ireland slipped for the sixth month in a row in August and were 1.9 percent lower year-on-year, the permanent tsb/ESRI house price index published on Thursday showed.

The average price of a house fell 0.3 percent in August after a 0.4 percent drop the previous month.

House prices started falling on a monthly basis in March for the first time in five years.

The average price paid for a house fell by 892 euros (620 pounds) to 300,375 euros in August and is now more than 10,000 euros lower than at the end of 2006.

"The index confirms that the actual rate of change in house prices across the country remains modest," said Niall O'Grady, head of marketing with permanent tsb bank.

"Since the start of this year, prices have declined by 3.3 percent on average," O'Grady said.

House price growth this year is expected to average 1.0 percent versus 11.8 percent in 2006, according to the latest Reuters poll. For 2008 economists expect house prices to be flat.

Irish house prices have more than quadrupled since the economy began to boom in the late 1990s and economists are watching the slowdown closely for signs of spill-over into a broader economy heavily reliant on the construction industry.