The head of the United Nation's climate science panel, Rajendra K Pachauri, has stepped down, amid claims that he sexually harassed a subordinate, reports AFP news agency.

In its press release on Tuesday, the Intergovernmental Panel on Climate Change stated it has agreed to designate vice-chair Ismail El Gizouli as acting IPCC chair.

"The designation of Gizouli follows the decision by Rajendra K Pachauri, PhD, to step down as chairman of the IPCC effective today."

“The actions taken today will ensure that the IPCC’s mission to assess climate change continues without interruption,” said Achim Steiner, Executive Director of the United Nations Environment Programme (UNEP), who facilitated the Bureau meeting. “We look forward to a productive session in Nairobi this week.”

Pachauri cancelled his attendance at meeting on global warming in Nairobi after a 29-year-old female researcher from the New Delhi-based think tank he heads, The Energy and Resources Institute (TERI), accused him of sending her inappropriate messages.

A leading voice on the dangers of climate change, Pachauri denied any wrongdoing, saying his email account and mobile phone were hacked.

On Monday, he was granted official "relief from arrest" for three days as police investigate the harassment complaint.