Activist groups have called on the UN General Assembly to create a new panel of independent experts to collect and preserve evidence of possible war crimes by all sides in Yemen's bitter conflict for future prosecution.

Some 60 groups, including Human Rights Watch and Amnesty International, called in a joint statement on Thursday for a fresh investigation.

They accused Saudia Arabia and the United Arab Emirates of an "aggressive lobbying campaign" to quash that Geneva-based expert panel set up four years ago.

Bahrain, Russia and other members of the UN Human Rights Council pushed through a vote in October to shut down its war crimes investigations in Yemen, in a stinging defeat for Western states.

"For too long, parties to the conflict in Yemen, including Saudi Arabia and Houthi forces, have committed atrocities with impunity," Agnes Callamard, secretary-general of Amnesty International, told a press conference.

The United Nations had failed the Yemeni people who have endured years of widely-documented suffering, she said.

"Bullying and bribing and corruption of the system has won the day," Callamard said.

"Saudi Arabia and the UAE and their allies shamelessly and aggressively lobbied states through their capital cities and got rid of the Group of Eminent Experts."