* Committee chair: it was an easy, unanimous decision
* Russian, Belarussian activists among possible laureates
* Appeal of Arab Spring candidates dimmed by violence
By Balazs Koranyi and Alister Doyle
OSLO, Oct 12 (Reuters) - The Nobel Peace Prize Committee announces its 2012 winner on Friday with prize watchers favouring dissidents from Russia and Belarus or religious leaders working on Muslim-Christian reconciliation.
"It was a unanimous decision and it was not particularly complicated," Thorbjoern Jagland, the head of the selection committee, told the Aftenposten newspaper.
Jagland said that the winner, decided several weeks ago, is generally known to the public and the decision could generate some controversy.
"I expect that there will be some debate, we hope there will be," Jagland told broadcaster TV2.
The prize will be announced at 0900 GMT.
Norwegian public broadcaster NRK, often thought to have strong sources, said there would be a single winner this year, unlike 2011 when three women won, and the prize could go to the dissidents in East Europe, a bishop in Mexico or the European Union itself.
Top Russian candidates include Lyudmila Alexeyeva, considered the grandmother of Russia's human rights movement, Svetlana Gannushkina and the civil rights society Memorial that she helps to lead, and Alexei Venediktov, the editor of the radio station Ekho Moskvy.
Criticism of Russia's human rights record grew louder this year as the government cracked down on free speech ahead of presidential elections. Some members of the punk band Pussy Riot were jailed for a protest in Moscow's main cathedral against Vladimir Putin, Russia's dominant leader for almost 13 years.
But picking a Russian may be politically risky as Norway has maintained healthy relations with Moscow and Jagland is also the secretary-general of the Council of Europe, which promotes human rights, democracy and the rule of law in its 47 member countries, including Russia.
A way to indirectly address the issue would be to place the award in Belarus, a close Russian ally, honouring jailed dissident Ales Belyatsky for his efforts to expose Europe's last dictatorship.
Belarus's parliamentary elections last month were dismissed by international monitors as a sham. EU foreign affairs chief Catherine Ashton said the vote "took place against the background of an overall climate of repression and intimidation".
Although the Arab Spring pro-democracy uprisings generated a slew of nominations, recent violence and disorder have made it more difficult to honour the region's transformation, leaving some religious leaders as favoured candidates.
The betting agency Unibet favoured Maggie Gobran, a Coptic Christian welfare worker who runs a children's mission in Cairo, while other mentioned include Nigerian religious leaders John Onaiyekan and Mohamed Sa'ad Abubakar, who have helped to calm their country's Christian-Muslim violence this year.
The committee received 231 nominations this year, including 43 organisations. It usually narrows the list to between 25 and 35 names at its first meeting to weigh candidates.
Other betting sites favoured Afghan women's rights leader Sima Samar and retired U.S. political science professor Gene Sharp, an advocate of non-violent struggle.