The Irish Refugee Council (ICL) has expressed concern about changes to the Refugee Act which could see asylum seekers detained for up to 21 days.
The new rules, which come into force on Monday next, extend the possible detention period for asylum seekers who are suspected of breaking immigration laws from 10 to 21 days.
The rules also allow for the designation of certain states as "safe countries" which the Council says makes it more difficult for asylum seekers to prove their case.
Hundreds of asylum seekers from the 10 EU accession states, as well as Romania and Bulgaria, will face a presumption that they are not refugees.
The move is aimed at deterring asylum claims from countries which are not considered oppressive.
The Council's legal officer, Ms Cabrini Gibbons, told ireland.com this places the "burden of proof" on the individual as the presumption is that they are not refugees.
Ms Gibbons said many asylum seekers have a distrust of authority and often have little English which makes it difficult for them to prove their case.
She said the Council welcomed some of the new rules like the prioritisation of applications by minors.
The Council supports the speedy processing of applications but not at the expense of a "full and fair process".
Commenting on the introduction of the new provisions, the Minister for Justice, Mr McDowell said: "Major advances have been made in recent years under this and the previous Government in speeding up the processing of asylum applications and in clearing the backlog of claims both in the Office of the Refugee Applications Commissioner and in the Refugee Appeals Tribunal.
"These extensive amendments, while fully consistent with the State's obligations under the 1951 Geneva Convention, will provide a more comprehensive framework for the fair and expeditious processing of asylum applications," he said.
