There has been a 7pc drop in car insurance, but young people, returning emigrants and those with a claims history are still paying "inordinately high" prices.
While the all-round decrease for the second year in a row is good news for many motorists, certain groups are still being stung by substantial bills, AA Ireland claimed.
"For the second successive year, the Central Statistics Office (CSO) findings in relation to insurance show a significant year-on-year drop," said AA director of consumer affairs Conor Faughnan.
"While this is a positive development, we're still a long way away from truly fixing many of the issues in our insurance system, which contributed to the price rises seen from 2015.
"It's true that some progress has been made in this space, but with each passing month it begins to feel more and more that the Government have moved their attention on to other matters and that motorists are simply being forced to get used to higher insurance prices.
"This is particularly true for anyone with an abnormal or non-standard driving history.
"Whether it's the case of a young driver or a returning emigrant, these cohorts are still seeing massive insurance bills, particularly in year one of driving in Ireland."
According to the CSO's Consumer Price Index, the average cost of motor insurance fell by 6.7pc between June last year and last month.
The AA said the small reduction has only benefited the "mainstream market of motorists with conventional risk profiles".
Groups such as returning immigrants, young drivers and those with penalty points or a claims history still pay "inordinately high prices in the ongoing insurance costs crisis", Mr Faughnan said.
Meanwhile, the average cost of running a family car for a year has fallen and is now €10,593.26, according to the AA's annual survey of motoring costs.
This is a decrease of around €100 compared with last year.
The AA's fuel prices survey also found the average cost of a litre of fuel has fallen by 2.5pc in the past 12 months.
However, it highlighted that the most recent drop in fuel prices came after a period of significant increases.