A team of European human rights experts has denounced the disciplinary use of solitary confinement in some Swiss prisons.
Members of the European Committee for the Prevention of Torture (CPT) also had strong words for the Geneva police over alleged force used during arrests.
The comments, published on Monday, were contained in preliminary remarks following the CPT's visit to Swiss jails in autumn last year.
The CPT said it was "concerned" over the use of disciplinary procedures and the punishments meted out in some Swiss prisons, especially in the use of solitary confinement.
It said it wanted to be informed within a month about measures taken to remedy the situation.
"[The inmates] receive only a Bible or Koran as reading material and in Aarau, Champ-Dollon and Zurich [prisons] from the first day they have no right to an hour of outdoor exercise," the experts said.
Champ-Dollon, near Geneva, has previously hit the headlines for being Switzerland's most overcrowded prison – a point which was also mentioned in the CPT report.
The committee has already instructed the Swiss authorities to ensure that inmates who are disciplined at the three prisons cited receive at last one hour of outdoor exercise a day.
As for the police, the committee said that apart from the Geneva force it had found no evidence of maltreatment of detainees.
The allegations of abuse levelled at the Geneva force mostly concerned arrests. The CPT said that there had been reports of kicks, punches and the use of police dogs as well as "strangling techniques" carried out for the regurgitation of drugs.
The experts said that they had heard of these methods being deployed even when a person was restrained or on the floor.
"Such acts are simply inacceptable and should be punished," said the CPT.
The Geneva force has been dogged by allegations of infighting and racism.
The complete report of the CPT's visit in September and October 2007 will be submitted to the Swiss government in spring 2008 and published later with the cabinet's approval.
These preliminary remarks come after the Swiss justice authorities revealed in October that the CPT had found no evidence of torture or abuse in the country's prisons.
A statement issued by the Federal Justice Office said that the authorities took "very seriously" the criticisms, observations and recommendations made by the CPT – without revealing at the time what they were.
swissinfo with agencies
There are around 120 detention centres in Switzerland with places for 6,741 inmates.
In September last year there were 5,888 people in custody.
Foreigners accounted for 69% of the total.
Women made up 5.7%.
EUROPEAN COMMITTEE FOR THE PREVENTION OF TORTURE (CPT)
Under the European Convention for the Prevention of Torture and Inhuman or Degrading Treatment or Punishment, CPT delegations have unlimited access to places of detention.
They also have the right to unrestricted access inside secure units and can interview detainees in private.
The "periodic" visit to Switzerland is one of 11 that the CPT undertook in 2007. Other countries included Spain, the Netherlands, Croatia and Moldova.
After each visit, the CPT sends a confidential report containing its conclusions and recommendations to the country concerned.