"Human rights are suffering in Libya as it continues to stall on reform ... despite the country’s efforts to play a greater international role," the London-based rights watchdog said.
Amnesty said it documented floggings for adultery, as well as indefinite detentions, migrant and refugee abuses, the disappearance of dissidents and security forces' immunity from prosecution, during a week-long visit to Libya in May.
Hundreds of people languished in jails after serving out their sentences, some of them held after statements obtained under torture used as evidence, it said.
Mainly African migrants, refugees and asylum-seekers faced arrest, detention and abuse on their way to seeking sanctuary in Italy or other European Union nations, it added.
"If Libya is to have any international credibility, the authorities must ensure that no-one is above the law and that everyone, including the most vulnerable and marginalised, is protected by the law," said Hassiba Hadj Sahraoui, Amnesty's Middle East and northern Africa deputy director.
"The repression of dissent must end," the report quoted her as saying.
Amnesty said forces, especially the Internal Security Agency, or ISA, continue to commit violations with apparently unchecked powers to arrest, detain and interrogate people suspected of dissent or terrorism.
"Individuals can be held incommunicado for long periods, tortured and denied access to lawyers," the report said.
However, the rights watchdog added that it had "observed a modest increase in the flexibility of the Libyan authorities towards criticism".
It noted for instance that families of the victims of a 1996 massacre by security forces of an estimated 1,200 prisoners are allowed to protest about their case.
But Amnesty said activists still faced harassment including arrest, and while Libya has released about 15 prisoners of conscience in the past two years, it has failed to compensate them for violations.
"Libya’s international partners cannot ignore Libya’s dire human rights record at the expense of their national interests," said Sahraoui.
"As a member of the international community, the Libyan authorities have a responsibility to respect their human rights obligations, and tackle their human rights record instead of concealing it.
"The contradiction of Libya being a member of the UN Human Rights Council, while refusing for the body’s independent human rights experts to visit the country is striking," she concluded.— AFP