Gardaí said they are investigating a number of incidents of criminal damage in Dublin after climate campaigners deflated tyres on SUVs.
Members of the so-called Tyre Extinguishers group have been using lentils to let air out of tyres in vehicles they describe as "gas guzzlers".
Since December, dozens of motorists in Dublin and Meath have been targeted, as part of an international campaign across numerous countries.
The group said the aim of the initiative is to try to reduce the use of SUV-type vehicles on the roads, particularly in urban areas.
The activists involved employ a tactic of putting lentils into tyre valves to release the air. A note is then left explaining that "we have deflated one or more of your tyres".
"You'll be angry, but don't take it personally. It's not you, it's your car."
The leaflet from Tyre Extinguishers also said: "We did this because driving around in urban areas in your massive vehicle has huge consequences for others."
On its Twitter account, the group has reported that so-called gas guzzlers have been disarmed in parts of Dublin and in Navan in Meath. 30 vehicles were targeted in the Donnybrook area last week alone.
Mark Kelly, the Managing Director of the School of Irish Archaeology, is among the motorists who have been targeted recently by the campaigners.
Air was released from tyres on two of his commercial vehicles on 10 June in the Portobello area.
He said the company had two events on in Navan and in Carlow that day but when he came outside, one of his SUVs, a Land Rover commercial vehicle, had a flat tyre.
"I just thought it was flat but when I went down the road, we had another SUV with a 16-foot commercial trailer, big, very obvious, and I noticed that two tyres were deflated."
He said he then "realised there was obviously more to it than it was and I saw the little note from the Tyre Extinguishers telling me that we're gas guzzlers and we're impacting on the environment".
Mr Kelly said as a small business, he is a sole trader, working very hard to support a family and employ people.
"So, to see this happen and also the financial loss that could have been potentially, we could have lost a lot of money that day, and that was very frustrating because we were targeted and we're not anybody's enemy."
Oisín Coghlan, the Chief Executive of Friends of the Earth, said he completely understands the frustration of the activists, "given that we're just not taking adequate action to cut our polluting emissions".
However, he said he is "a bit concerned about the impact on individuals, whereas I think the real targets here should be the Government and the companies".
"Government needs to take enough action to reduce transport emissions and companies are spending about €2,000 per car in advertising."
Mr Coghlan said the focus should be on regulation of advertising and on taxing appropriately so that the more polluting cars are not attractive anymore.
Gardaí said they are investigating a number of incidents of criminal damage that occurred in the Churchtown area of Dublin in the early hours of 14 June and also in the Ranelagh area of Dublin on the night of 21 June.
They said their investigations are ongoing.
