The UN's Human Rights Commission has ended its annual meeting in Geneva facing unprecedented calls for reform.
Louise Arbour was critical of her own commission
UN Secretary General Kofi Annan said the body's declining credibility was undermining the UN as a whole.
Human rights commissioner Louise Arbour described the commission as selective and unfair, saying it was failing to monitor human rights abuses.
Critics say the commission is arbitrary in its assessment of human rights records of individual countries.
Mr Annan has called for a new structure involving only countries that have a proven record of upholding human rights.
"We have reached a point at which the commission's declining credibility has cast a shadow on the reputation of the United Nations system as a whole, and where piecemeal reforms will not be enough," Mr Annan told the commission.
He is proposing a smaller council whose members already have a proven record of upholding human rights.
Small countries with poor human rights records, such as Belarus, Burma, Cuba and North Korea, were criticised by the commission while nations like China, Zimbabwe and Russia were left out.
"There is something fundamentally wrong with a system in which the question of the violation of human rights and fundamental freedoms in any part of the world is answered by reference to just four states," said Louise Arbour.
On Sudan, the commission passed a resolution condemning human rights abuses in Darfur but failed to censure the Sudanese government, which is a member of the commission.
Nations criticised by the commission do not face penalties but most governments are keen to avoid being named and shamed.
Critics say the commission cannot function when its 53 member states, among them China, Cuba, Sudan and Zimbabwe, are in charge of judging themselves.
Joanna Weschler, of Human Rights Watch said: "This session has been a powerful demonstration of the need to scrap the commission and replace it with something better."
Amnesty International's Peter Splinter criticised the commission's "selectivity and double standards".
During the six-week session, which ended on Friday, the commission appointed an investigator into counter-terrorism measures and human rights abuses but rejected a proposal to look specifically at Guantanamo Bay.
The fate of the commission will be decided when the UN's 191 member states meet at the General Assembly in New York to discuss reform of the organisation.