The Justice Minister and Garda Commissioner are being asked to clarify what 'immigration checks' will be carried out under a wider plan to tackle crime in Dublin.
Migrant Rights Centre Ireland Director Edel McGinley was speaking after the checks were included as part of a strategy to increase security in the capital.
Under the the plan, Gardaí have said there will be "planned days of high impact visibility in the city centre involving checkpoints; execution of warrants; service of summonses; intelligence-led searches and arrests; immigration checks, and enforcement of road traffic offences."
Ms McGinley told Newstalk Breakfast the approach is very unclear.
"It's quite unclear to us what's being planned," she said.
"There's a kind of a blanket statement around immigration checks that will be carried out by An Garda Síochána.
"It doesn't make sense to us at all".
'Safety is important for all'
Ms McGinley said they are seeking clarity on the statement.
"We're writing to the Minister and Commissioner to clarify this and explain what exactly it means," she said.
"Safety is important for us all, whether you're a woman walking down the street at night, a tourist, a worker.
"That's no less important for immigrants - who are also very subject to frequent attacks while working or living in the city."
Ms McGinley said there are concerns about the risk of ethnic profiling.
"What we're concerned about really is.... this is an unjustified and disproportionate measure that's being introduced by way of combating these attacks," she said.
Ms McGinley acknowledged while Gardaí can stop and question people suspected of a crime or a public order offence, criteria needs to be clear.
"What's being put out there now is that is that everybody will be asked," she said.
"How would this work? Is everybody walking down the street supposed to be subject to stops and searches?
"We're singling out a whole group of people at the moment, blanketly.
"You can if you've just cause, absolutely, ask people for documents - but here's no oversight on this.
"Our legislation doesn't provide for recording incidents like this to be able to stand over that, to explain whether it's racially motivated or not.
"You have to justify why you stopped somebody."
Ms McGinley added: "We think it's unworkable, we think it's a practice that needs to be eliminated.
"There's been a rowback on elements of this operation so far - we want to see this clarified."