The charge was made to prison officers, who have met dozens of ‘aliens’ before they were deported on the first available flight, but the claim has been dismissed by immigration officials.
However, the Irish Refugee Council said the claims tallied with information they had been received about arrivals in Dublin and Cork airports.
Immigration officials have a right to refuse people leave to land for various reasons, including the lack of a work visa or funds.
But every person applying for asylum has to, under international conventions, be allowed to remain in the country.
Superintendent John Mulligan, of the Garda National Immigration Bureau, said: “If someone is refused leave to land, it’s made very clear to them the reason.
“If we have people coming through the airport and they do not speak English, then we will find someone to speak to them.”
If someone is applying for refugee status, Supt Mulligan said, then they are transported to the Refugee Applications Centre. Those refused leave to land are sent back on the next available flight. But there might not be a flight for one or more days.
They are moved to Mountjoy in Dublin or the Bridewell in Cork.
In prison, they are entered into the admissions book as ‘aliens’ and their photographs taken.
In Mountjoy they are kept in a small holding cell, sometimes with six other people.
Prison insiders described how some claimed to have been told they were going to an hotel for a night and the first they knew about being sent to prison was on arrival at the doors. This claim has been also been denied by immigration officials.
But gardaí have also said they were told by some they had wanted to apply for asylum but were not given an opportunity.
Others are from EU accession countries and took a chance on travelling before their countries sign up next year.
The Irish Refugee Council claims a drop in the number of asylum seekers is partly due to an increased number of arrivals being refused leave to land.