The UN Human Rights Council on Friday decided to appoint a special rapporteur for Burundi, where an investigation by the world body has spoken of a "deteriorating" rights situation.
A resolution on Burundi brought by the European Union was adopted by 21 votes for, 15 against with 11 abstentions.
The special rapporteur will be tasked with following the situation in the central African country and making recommendations to the government.
Burundian ambassador Renovat Tabu opposed the resolution, saying "African solutions must be found for African questions."
"Burundi does not need an external mechanism to promote human rights," Tabu added.
The election of Evariste Ndayishimiye in May last year as Burundi's president had fuelled hopes of change in a country wracked by civil war, political turmoil, summary executions and arbitrary detentions.
But in its fifth report published on September 16, the UN Commission of Inquiry on Burundi said despite a few improvements, abuses were rife.
"Since President Ndayishimiye's inauguration 15 months ago, not only have grave human rights violations continued to occur, but in some respects the situation has deteriorated," commission chairman Doudou Diene said in a statement.
"Members of opposition parties... are still regularly targeted by abusive restrictions and are subject to grave human rights violations such as disappearances, arbitrary arrests and detentions and torture," the UN statement said.
Burundi had refused to cooperate with the UN investigative team, which accused security forces of actions that could constitute crimes against humanity.
The resolution adopted on Friday asked Burundi to cooperate with the rapporteur and allow unfettered access across the country.
Burundi has been in crisis since 2015, when then president Pierre Nkurunziza ran for a controversial third term and was re-elected in polls boycotted by most of the opposition.
The announcement of the third term bid triggered a crisis in which at least 1,200 people were killed and more than 400,000 forced into exile. The UN says the violence was mostly carried out by state security forces.
Nkurunziza remained in power until elections in May 2020 handed the presidency to his handpicked successor Ndayishimiye. Nkurunziza died soon after the vote.
The commission was created by the UN Human Rights Council five years ago to investigate abuses.