"The human rights situation in Bahrain remains an issue of serious concern to us," Swiss ambassador Alexandre Fasel said, speaking on behalf of the 32 countries, including the United States, Britain, France and Germany.
Addressing the UN Human Rights Council, Fasel called for the creation of a rights commission for prisoners and detainees and a special investigation unit for probing and prosecuting alleged violations by security officials.
Swiss ambassador said his diplomat colleagues were concerned about reports of "harassment and imprisonment of persons exercising their rights to freedom of opinion and expression and of peaceful assembly and association, including human rights defenders."
"Human Rights Watch also joined the call for Bahrain to invite the UN Special Rapporteur on Torture."
The countries also said they were worried by "the lack of sufficient guarantees of fair trial, and by the detention of minors due to their participation in demonstrations," and urged the Bahraini regime to "look at alternatives to detention".
Fasel voiced concern "that there is insufficient accountability for human rights violations" and expressed alarm at reports that people reporting human rights abuses or cooperating with the United Nations were facing reprisals.
The countries called on Manama to "appropriately address all reports of torture and ill-treatment of detainees and ensure full investigation and prosecution of these cases",AFP reports.
They urged the Persian Gulf kingdom to accept a visit by the United Nations top expert on torture.
Human Rights Watch also joined the call for Bahrain to invite the UN Special Rapporteur on Torture.
Human Rights Watch said it was "extremely disappointing that some states such as Italy and Spain put politics before rights and did not lend their voice in support".
Bahraini protesters hold placards portraying Sheikh Ali Salman, head of the Shiite opposition movement Al-Wefaq, on March 24, 2015, during a demonstration against his arrest, in the village of Daih, west of Manama.
Tiny but strategic Bahrain, which is home to the US Navy's Fifth Fleet, has been rocked by unrest since a 2011 uprising demanding a constitutional monarchy and more representative government.
At least 89 people have been killed over the past four years, while hundreds have been arrested and put on trial, rights groups say.