UN High Commissioner for Human Rights Navi Pillay on Friday said anyone who had committed abuses during the mass protests in Yemen must not be allowed to evade justice.
The UN commissioner in a statement urged decision-makers in Yemen to respect the prohibition in international law against amnesties for gross human rights violations.
"I have been closely following the events in Yemen, particularly the very contentious debate about an amnesty law to be presented to parliament shortly," Pillay said in a statement.
Pillay said that international law and UN policy are clear.
"Amnesties are not permissible if they prevent the prosecution of individuals who may be criminally responsible for international crimes including war crimes, crimes against humanity, genocide, and gross violations of human rights."
The high commissioner said the UN has information that some of the crimes she was referring to were committed in Yemen during a period during which an amnesty was under consideration.
"Such an amnesty would be in violation of Yemen's international human rights obligations," said Pillay.
For a society emerging from a period of violent conflict a "victim-centred approach" to justice is critical to restoring stability, she said.
Victims have the right to justice, the truth, remedy and reparation which are internationally established she said.
On November 23, after months of street protest against his rule Saleh signed an accord in Riyadh making provision for him to step down and allow presidential elections on February 21, in exchange for immunity for himself and his family.
The draft amnesty law "is a result of the agreement", Ravina Shamdasani, a spokeswoman for the UN High Commissioner, told AFP.
Any new legislation in Yemen should respect the principle of equality before the law, Pillay said in her statement.
This meant there should be no discrimination between government supporters or those in in opposition and there should be no distinction based on family connections she noted.
"Every individual who commits a crime is accountable and should not be allowed to escape justice."