An unusual war of words is tarnishing the staid Nobel Peace Prize committee just before its main task this week – picking a 2015 winner from candidates such as Pope Francis, Colombian peace negotiators or those helping Syrian refugees.

The secretive five-member Norwegian committee is under an unwelcome spotlight after Geir Lundestad, its secretary for 25 years until 2015, questioned the wisdom of some prizes and pokedcriticism at many members in a book last month.

Lundestad revealed, for instance, that the 2009 prize to US President Barack Obama had failed to live up to the committee’s hopes, that one member almost quit in disgust at the award to climate campaigner and ex-US vice president Al Gore in 2007, and that one member spoke out against any prize for a pope.

In retaliation for the book, Secretary of Peace, the committee issued a rare statement, accusing him of breaking a 50-year confidentiality rule.

And he is being evicted from an office at the Norwegian Nobel Institute where he served as director and attended committee meetings, without a vote.

This has touched off the worst row since a pro-Israeli committee member quit in 1994, denouncing the inclusion of Palestinian leader Yasser Arafat in a joint prize with Israel’s Yitzhak Rabin and Shimon Peres for peace efforts.

The book piles pressure on the usually anonymous committee, which tries to cultivate an aura of Olympian detachment in judging world affairs, to pick a worthy winner this year for the eight million Swedish crown (€855,450) prize.

Thørbjorn Jagland, an ex-Norwegian prime minister and former committee chair who is still on the committee, hit out at Lundestad’s criticisms on national NRK television.

“I am not sure it strengthens the [committee’s] reputation when he writes that the current leader [Kaci Kullmann Five] is weak, the previous one [Jagland] was actually a fool and the one before[Ole Danbolt Mjøs] hadn’t a clue about foreign policy.”

Bookmakers have had Pope Francis as favourite for his work for peace and calls for environmental protection

Other experts reckon the prize will rebound.

“It takes some of the mystery out of the prize,” said Kristian Berg Harpviken, head of the Peace Research Institute, Oslo. But he said the dispute may blow over: “The prizes speak for themselves.”

Asle Sveen, a historian of the prize, also said: “We have a peace prize next [this] week. The internal strife will soon be forgotten.”

Kullmann Five will announce the 2015 winner on Friday, at 0900 GMT.

Jagland was so irked by Lundestad that he issued a statement rejecting suggestions that he had relied on Lundestad’s drafts of speeches at prize ceremonies, rather than write his own.

Former high-profile and outspoken Nobel Peace Prize committee secretary Geir Lundestad retired late last year.

Lundestad says the prize, named after Swedish philanthropist and industrialist Alfred Nobel, will easily shake off the internal details he describes, which he said was a blow for greater openness.

Bookmakers have had Pope Francis as favourite for his work for peace and calls for environmental protection, ahead of candidates including Novaya Gazeta, a Russian newspaper critical of President Vladimir Putin.

Others are Colombian President Juan Manuel Santos and the FARC leftist rebel commander Rodrigo Londono who pledged on September 23 to end a 50-year war within six months.

Jan Egeland, head of the Norwegian Refugee Council, said that a prize might honour people working with refugees from Syria.

Harpviken’s personal favourite is German Chancellor Angela Merkel, who has spoken out on the need to change European asylum policy. The UN refugee agency UNHCR, which won in 1954 and 1981, could also be a contender.

Nobel Prizes in years ending with ‘5’ – marking decades since the 1945 bombings of Hiroshima and Nagasaki – have often gone to campaigns against nuclear weapons. That could mean a prize for Iran’s promise to limit its nuclear programme in return for a lifting of sanctions.

Other nominees include former US spy agency contractor Edward Snowden.

All other Nobel prizes are awarded in Stockholm – Physiology or Medicine (today), Physics (tomorrow), Chemistry (Wednesday), Economics (Monday, October 12), while the date for the Literature prize has not yet been set.

Bookmakers have writers including Svetlana Alexievich of Belarus and Haruki Murakami of Japan among favourites for the literature prize.

An annual evaluation by Thomson Reuters, based on the number of times an expert’s work is cited in published papers, indicated that scientists behind the invention of a gene editing technology were among contenders for the Chemistry prize.