An immigration, detention and US citizenship counsellor at the Irish Pastoral Centre in Boston has said he has never seen such fear among the undocumented community as exists now.
It comes as a 19-year-old Irishman is due to be deported from the US to Ireland this week after he overstayed his visa by seven years.
Dylan O'Riordan, who was born in Galway, moved to the US with his parents when he was 12. Both his mother and father are Green Card holders.
US President Donald Trump has in the past vowed to clamp down on illegal immigration in the US.
Speaking on RTÉ's Morning Ireland, Kieran O'Sullivan said that 34 Irish immigrants were deported in the past year, which is an increase on the previous year.
It is believed there are an estimated 50,000 undocumented Irish people living in the US.
Mr O'Sullivan said that the Irish Pastoral Centre has been providing help and advice to undocumented immigrants for 30 years.
He said there had been a number of high profile detentions in the area in the last year and it was disturbing that those detained can spend up to five weeks in jail while the paperwork is being processed.
Mr O'Sullivan said it is terribly upsetting to the families.
Congress had, he said, failed to enact any meaningful immigration reform and the avenues towards achieving legal status were very difficult.
He said the majority of undocumented did not intend to break the law and many were paying tax.
Mr O'Sullivan dismissed as "nonsense" the idea that the undocumented community were a threat to the country.
"We would see comprehensive immigration reform as being the answer to the problems we are facing today," he said.
"The majority of the undocumented Irish here work hard, they pay taxes and they're only looking to make a better life for themselves and their families and this notion that's out there, that they're a threat to the country, is nonsense."