The world’s top climate change official has protested his innocence after being accused of sexual harassment by a 29-year-old researcher at his organisation.

The female employee lodged a complaint with the Delhi Police accusing Rajendra Pachauri, a 75-year-old Nobel Peace Prize winner, of repeated inappropriate behaviour, both physically and through emails, texts and WhatsApp messages.

Dr Pachauri, the chairman of the UN’s Intergovernmental Panel on Climate Change (IPCC) – which plans to broker a global treaty to tackle global warming in December – vigorously denies all allegations. It is understood that the researcher works at The Energy and Resources Institute (TERI) think-tank in New Delhi, where Dr Pachauri is director-general.

The respected academic said he had been a victim of hacking, claiming his email, mobile phone and WhatsApp messages have been hacked and that cyber criminals have used his computer without authorisation to commit criminal activities.

Rajendra Pachauri, a 75-year-old Nobel Peace Prize winner, has been accused of repeated inappropriate behaviour (Getty Images)

“Your questions have no connection with the truth,” Dr Pachauri told India’s Economic Times newspaper when approached with details of the allegations.

He claimed there was evidence of “misuse of my computer resources and communication devices, without my permission or consent”. The Independent was unable to reach Dr Pachauri yesterday.

However, reports in India suggested the police were in the early stages of investigations. Police granted Dr Pachauri “interim protection” from arrest until 23 February to enable him to “seek necessary relief” after he handed over his laptop to officers, local media reported.

The timing of the case is particularly awkward for Dr Pachauri because it comes in the run-up to a crucial summit in Paris in December at which world leaders have pledged to agree crucial cuts to carbon emissions in the battle to curb global warming.

As chairman of the IPCC, Dr Pachauri will oversee the talks. His Nobel prize was issued to him and Al Gore jointly for their role in promoting climate change.

But despite his clear commitment to tackling climate change, Dr Pachauri has proved a controversial character at times.

In 2010, he admitted that an IPCC report from 2007, which claimed there was a “very high” chance of glaciers disappearing from the Himalayas by 2035, was way off the mark.

The IPCC lost a lot of credibility over the incident, which climate sceptics used to try to discredit the entire organisation – a task made easier by Dr Pachauri’s refusal to issue a personal apology.

“You can’t expect me to be personally responsible for every word in a 3,000-page report,” he said in a defiant interview in which he also rubbished newspaper stories saying he had a lavish lifestyle and wore $1,000 suits.

“It’s ridiculous and it’s a bunch of lies. There is a taylor who stitches all my suits for 2,200 rupees (£30),” he said.