Insurance Ireland has said the industry is "absolutely not acting like a cartel".
Director of government affairs at Insurance Ireland Declan Jackson said rising car insurance premiums were being caused by soaring claims costs, despite a lack of evidence shown to the Oireachtas.
Yesterday a committee found that consumers have effectively been told to accept increases without explanation.
However, Mr Jackson said the hikes were of no benefit to insurers.
In response to a comment that some had seen insurance hikes of 70%, he said: "That level of increase is not in the interests of the industry because it makes insurance less affordable for motorists.
"In turn that means people are less likely to take out insurance."
He also said: "There is absolutely no cartel."
Yesterday, a new reprt said car owners hit with up to 300% insurance hikes had been “thrown to the wolves” of the insurance sector by State institutions who are charged with protecting them.
Insurance companies are heavily criticised by the report which states that a “closed mentality” and unwillingness to share data is a contributory factor to the recent rise in motor insurance premiums.
It may also hinder the entry of new operators into the “dysfunctional” Irish market, the Joint Oireachtas Committee on Finance's Report on the Rising Costs of Motor Insurance concluded.
The report found that on average premiums have increased by 37%, but in some cases premium hikes have been in the order of 200%-300%.