The Minister for the Environment has criticised what he describes as a "sinister fringe" taking part in protests against Irish Water.
Alan Kelly was speaking as he confirmed that people who do not pay their water bill will not have their supply cut off or reduced.
The Government insists the charge will be "modest", but it may be after next week before there is clarity on the exact cost.
Minister Kelly stressed that the vast majority of protesters were not violent, but he was concerned about the “sinister” element.
“I worry from a society point of view and from being a citizen of this country, about the motives of a very, very, very small quantity of those people,” Mr Kelly said.
“I believe there is a fringe out there who are using genuine people, genuine protestors for other political ambitions.
“It is sinister, I agree with my colleague, and that would be the feeling of people inside and outside politics,” Mr Kelly said.
Last night a group of approximately 200 people protested outside Coolock Garda station in response to the arrests of three protesters earlier Wednesday in Santry. There were reports of physical confrontations. There were no arrests made.
Health Minister Leo Varadkar, speaking to Newstalk Breakfast, said there is a “very sinister fringe” among water charges protesters who are behaving in a violent manner. Mr Varadkar claimed that some protesters are particularly aggressive towards gardaí and are spreading misinformation.
“What I’m worried about is that it is only a matter of time before someone gets hurt,” he said.
"While there are a lot of people protesting legitimately and reasonably, this fringe element is very sinister.
"It is a very nasty fringe to these water protests.
Mr Varadkar called on the parties who oppose water charges to condemn violent actions of protesters.
"I think it is really important that Sinn Fein, the Austerity Alliance and Independents all condemn the violence and the abuse of gardai that occurred yesterday,” Mr Varadkar said.
Anti-Austerity Alliance Councillor Michael O’Brien, who was involved in the protests outside Coolock Garda station, rejected Minister Varadkar’s claims, saying they are an effort to discredit the protests.
“This is a desperate attempt by the Minister to try to discredit the anti-water charge movement and to cover up for the thuggish behaviour of the Gardaí,” Mr O’Brien said.