Rports alleging that detainees have continued to be tortured in Venezuela following the seizure of President Nicolás Maduro by US forces in January are concerning, the UN's High Commissioner for Human Rights, Volker Türk, says.

Maduro has been replaced in power by one of his loyal allies, former Vice-President Delcy Rodríguez, under whose leadership an amnesty bill has been passed into law.

Türk welcomed the amnesty law but warned that "structural and systemic human rights concerns have persisted" in Venezuela despite Maduro's ousting.

Venezuelan officials have not yet reacted publicly to Türk's remarks but have in the past dismissed allegations of torture as politically motivated.

Türk said many Venezuelans remained in "arbitrary detention" despite the passing of the amnesty law last month.