The groups including Amnesty International, Human Rights Watch, and Doctors Without Borders said in a series of separate statements and at a news conference in Athens that the proposed changes would restrict the right of refugees fleeing wars in Syria, Iraq and elsewhere to seek international protection in the European Union.
"They are putting up obstacles to access the asylum system which is a basic human right. It's moving to mindset of punishment," said Gabriel Sakellaridis, head of Amnesty in Greece. "The changes will lead to the creation of a large group of people who do not have the proper papers. They will be even further marginalized in society."
The proposed changes are due to be voted on in Greece's parliament this week, and include expanded powers to detain migrants whose asylum applications are being processed or have been rejected as well as plans to ramp up deportations.
Greek authorities are struggling to cope with a sharp rise in the number of arrivals over the summer months on Lesbos and other islands in the eastern Aegean Sea where EU-funded camps are suffering severe overcrowding and outbreaks of violence.
According to recently reported EU data , Greece is now Europe's busiest entry point with more than 47,500 arrivals this year through Oct. 6, a 29% increase from 2018. The report said Greece has received more than 2.2 billion euros ($2.4 billion) in EU assistance but is failing to make use of a 2016 EU-Turkey agreement that allowed for the deportation of many migrants from Greece back to Turkey.
"Returns of all new irregular migrants from Greece to Turkey under the (agreement) is a continuous challenge. Greece has managed to return only 1,908 migrants under the (agreement), with the pace slowing and around 100 returns this year. This is a major obstacle to progress, also linked to the lengthy asylum procedures currently in place in Greece," the report said.
Greece's conservative prime minister, Kyriakos Mitsotakis, who was elected during a mid-summer surge in migrant arrivals, said his new government needed to take immediate action to try to ease overcrowding at migrant camps.
"I'll be honest: Over the past few months, my country has been accepting flows of refugees and migrants that are disproportionate to its size and population," Mitsotakis said. "Our border islands are suffocating."
__ Elena Becatoros in Athens contributed __ Follow Gatopoulos at https://twitter.com/dgatopoulos and Tongas at https://twitter.com/theodoratongas