Greek detention officers treat migrants "like caged animals" and prison conditions for inmates have deteriorated, the Council of Europe's anti-torture committee said in a report today.

Publishing a detailed account of a study completed last March but kept under seal pending a response from Athens, the panel lamented poor hygiene conditions, overcrowding and inadequate medical attention for migrants.

It describes a cell holding families with small children as being "in an execrable state", with toilets not working and sewage on the floors.

"No special measures were taken as regards the care of babies, young children and juveniles," it said of holding centres visited in January last year on an ad hoc basis.

"Everyone was treated the same -- like caged animals," said the report by the European Committee for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment (CPT).

"The CPT's delegation received many allegations of ill-treatment of irregular migrants by police officers ... consisting primarily of punches and kicks to the head and body," it added.

The CPT also faulted Greece on the lot of Greek inmates, saying it had "observed a steady deterioration in the living conditions and treatment of prisoners over the past decade".

The January 2011 visits to Greek jails "confirmed that a regulated prison system, as aspired to in law, has given way to the practice of warehousing prisoners".

In Greece's response, the CPT said "the Greek authorities demonstrate their willingness to cooperate with the Committee in order to improve the treatment of persons deprived of their liberty in Greece".

The reply also "provides information on the measures being taken to address the concerns raised by the Committee, notwithstanding the very difficult economic situation faced by the country."

The 47-member Council of Europe promotes cooperation on legal standards, human rights, democratic development, the rule of law and cultural matters.

Unlike the European Union, it cannot make binding laws.