Resistance by political groups and human rights associations is brewing over an agreement reached last week by EU member states on the controversial Return Directive.
A vote on the directive is scheduled for next week at the European Parliament.
The European Association for the Defence of Human Rights (AEDH) yesterday wrote to MEPs calling on them to vote against the directive.
Calling the agreement "repressive", the association said the deal was not acceptable because it fell short of international standards of protection in many respects.
"We cannot accept that the approval of this directive would uphold the detention of men, women and children for up to 18 months simply for being illegally staying," Pierre Barge, chairman of ADEH, said in his letter to MEPs.
Mr Barge said that by emphasising the notion of removing third-party nationals, paving the way for a policy of systematic detention, not establishing adequate standards of protection and proportionality, placing itself below the bar set by international standards, and using the absence of legislation in nine out of 27 European countries as a pretext, the directive contributes to a hardening of existing migration policies that approaches repression.
"This cannot be in line with your vision of a progressive Europe that respects human rights," the association said.
The leftist parties in the European Parliament also made it clear they will try to block the directive.
Addressing a press conference in Brussels, Francis Wurtz, president of the GUE/NGL group, said the agreement on the Return Directive negotiated between the Council and Parliament is unacceptable in both form and content.
"Our group rejects the very essence of this directive and will table amendments in plenary aiming to eliminate the articles providing for 18 months' internment in closed detention centres, a five-year re-entry ban into EU territory, the possibility of repatriating migrants to countries of transit (such as Libya, where the human rights situation is well known) as well as the repatriation of unaccompanied minors."
The Socialist Group - the second largest in the European Parliament - is also against the directive particularly on the detention provisions.
The ministerial agreement, which has been three years in the making, provides for common standards and return procedures as well as clear, transparent and fair common rules dealing with third country nationals who stay illegally in EU member states.
One of the most controversial provisions is that illegal immigrants can be detained for a maximum 18 months if found to be illegally on EU soil.
Malta agreed to this deal although it would not be hard-hit by many of the provisions of the directive as its laws already allow for an 18-month detention period similar to the one agreed by EU ministers.
Following amendments introduced by the European Parliament, the directive is only intended to apply to visa over-stayers and not to illegal immigrants landing on EU shores by boats, as is the case with the majority of illegal immigrants coming to Malta. According to the new agreement, member states will now be obliged to provide legal aid to asylum seekers in order to make sure they present their case for asylum in the best way possible.
The EPP-ED group, the largest political group in the European Parliament, agrees with the agreement reached by the Justice and Home Affairs Council.