They were up by 10pc, the first time in two years that increases were in double digits.
Prices have risen now for 12 months in a row.
The European Central Bank (ECB) is poised today to deliver its third rate cut this year.
Figures from the Central Statistics Office (CSO) show prices increased by 10.1pc in the year to August.
Experts said it was the highest rate of annual increase since September 2022.
In Dublin, they were up by 10.8pc, and prices outside the capital were up by 9.6pc. Prices rose by 0.9pc in the month of August alone.
Independent economist Austin Hughes said there was concern the market could be overheating.
“We are in double-digit property price inflation territory, incomes are rising, the budget put more money in people’s pockets and interest rates are falling,” he said.
“Understandably, this will stoke concerns of overheating.”
He said the demand for property will outstrip supply for a while, leading to higher prices.
However, in time, with credit growth constrained, such rapidly rising property prices would mean affordability would squeeze out some of the price inflation.
“Our property problems are no less real than before, but they are significantly different than at the time of the Celtic Tiger,” Mr Hughes said.
December’s reduction and a series of cuts next year could take the refinancing rate to 2.15pc
Back then, mortgage lending was out of control, but it is constrained now by Central Bank lending limits.
Huge numbers of houses were being built then, but there is a chronic shortage of homes to buy now, which is driving up prices.
The latest increase came despite a fall in home sales, the CSO data shows.
In August, first-time buyers nationally paid a median, or mid-point, of €360,000 for a home.
This is up by €33,000, or 10pc, compared with the same month last year.
In August, the median price of a home in Dublin was €485,000.
This is up €52,000, or 12pc, when compared with the same month last year, Mr Hughes calculated.
CSO statisticians said new home prices in the three months to June were 7.4pc higher than in the corresponding quarter of last year.
The ECB is expected to reduce its refinancing rate – the one trackers are priced off – by 0.25 of a percentage point to take it to 3.4pc. A similar cut is expected in December.
Independent economist Simon Barry said markets were pricing in a total of one percentage point in cuts next year.
December’s reduction and a series of cuts next year could take the refinancing rate to 2.15pc.
That would mean a typical tracker mortgage rate will have fallen from 5.5pc to 3.15pc by the end of next year, if all the predicted cuts are implemented.
ECB policymakers will meet in Slovenia to decide whether to reduce rates further and up the tempo of cuts.