The Gardaí paid private companies more than €4.7m to tow and store people's vehicles last year.
That is an increase of 16% on the year before.
The Gardaí often use private companies to arrange for the removal of vehicles after a breach of road traffic laws.
They can also be seized for an investigation, and are often stored in a garage for several days.
According to details released under the Freedom of Information (FOI) Act, the Gardaí have paid private companies more than €12.2m for this over the past three years.
In 2017, the cost came to just over €3.4m, rising to nearly €4.1m 2018 and more than €4.7m last year.
In 2019, the highest amount was in Dublin at €1.3m - followed by €467,000 in Cork and €426,000 in Galway.
Conor Faughnan from the AA says there are several reasons why cars are seized.
"Cars are seized because they don't have valid NCTs, they're in dangerous conditions.
"Cars are seized when they're not properly insured.
"I suspect the recent increase might be down to Clancy Amendment; people will be aware this was a toughening of the legislation recently which meant that the Gardaí could impound the car of a learner permit holder who was unaccompanied.
"There have been quite a number of those as well - probably enough to explain the increase".
The Garda press office did not respond to requests for comment.