Sinn Féin leader Mary Lou McDonald said Minister for Justice Helen McEntee and Garda Commissioner Drew Harris should resign.
Her comments follow a knife attack and subsequent violent disorder in Dublin city centre on Thursday night.
Speaking to reporters on Friday near the scene of the knife attack, Ms McDonald said there had been an “unacceptable failure to keep people safe” on Thursday night.
Ms McDonald said a “mob fuelled by hate” had wreaked havoc on the city.
“The cold truth and the reality that we must confront today is that the Gardai lost control of the centre of our capital city.
“A mob was allowed to shut down the centre of the city.
“Public transport locked down.
“People stranded in the city.
“Members of the public, families and workers terrified in what was a threatening and volatile atmosphere.
“This was an unacceptable, unprecedented collapse in policing.
“The idea that this violence was unforeseeable is frankly nonsense.
“These hate-filled mobs have threatened and brought violence to our streets before.
“This shouldn’t have happened and, let me be very clear, it can never happen again.”
She said she has “no confidence” in Ms McEntee and Mr Harris.
Ms McDonald said there had been a “an unacceptable, unprecedented collapse in policing” and that a problem leading to Thursday’s riot had been “building for months”.
“I do not say the following lightly, but it must be said.
“I have no confidence in how Dublin is being policed.
“The people of this city have the right to be safe on their streets, in their homes and in their communities.
“The gardaí have my full support but, given the catastrophic operational failures last night, I have no confidence in the Justice Minister, and no confidence in the Garda Commissioner.”
She later added: “They should resign, both of them.
“We clearly now need a change in government, but also a change in leadership of An Garda Síochana.”
