Moscow  - A man the Kremlin warily views as unpredictable is a shoo-in for what is arguably the most powerful non-government appointment in post-Communist Russia, experts said Monday, as church leaders held council to elected a new Orthodox patriarch.

Metropolitan Kirill of Smolensk and Kaliningrad, 62, the conspicuous head of the Russian Orthodox Church's external relations department and the church's interim leader, is the candidate most likely to win out of three chosen by senior clergy on Sunday.

In fact, there are no set rules in the church's charter for the succession process, heightening the Byzantine whispers that accompany this week's closed-door vote. Indeed, church heads once drew lots to appoint a new patriarch after the October Revolution of 1917.

The election comes at the peak of the Orthodox Church's influence after a two-decade-long renaissance that spread through all the former Soviet states with the collapse of the atheist communist regime in 1991. The iconic leader of this rebirth, former Patriarch Alexey II, passed away last month.

The only viable opponent to Kirill, and the man widely seen to be favoured by the Kremlin, is the conservative Metropolitan Kliment, 59, the powerful head of the church's administration at its Moscow headquarters.

"Of course, Kliment would be better from the Kremlin's point of view. Kirill is a stronger figure, more independent," prominent Russian journalist Maxim Shevshenko, who heads the Centre for Strategic Studies of Religion and World Politics, told Deutsche Presse-Agentur dpa.

Kremlin efforts to blacken Kirill's reputation in the mid 1990s by exposing an alleged smuggling scheme under which his department imported cigarettes as humanitarian aid to bypass customs tax failed to halt his rise, said Moscow-based religions expert Geraldine Fagan, of the Norwegian religious affairs centre Forum 18.

An effort to rally conservative bishops around Kliment also seemed to have gained only limited momentum in the frenzied backstage manoeuvring since Alexei's death.

Kirill holds the higher ground as the interim leader going into the vote. It is he who may set the process by which the new church head is voted in.

A panel of religious experts of all stripes was convinced Monday that Kirill was the only candidate with wide-enough public renown and gravitas for the job.

Now the church's top diplomat, Kirill made his career as the public face of the Russian faith in one of the few departments allowed more-or-less free rein in Soviet times.

A charismatic figure, he makes frequent public appearances on television speaking out on everything from family planning to the financial crisis. Experts say he is a liberal moderniser who favours closer relations with the Vatican.

But open attempts by the Kremlin to meddle in the vote could backfire as the post-Soviet church enjoys a greater measure of public trust than almost any other social institution, experts agreed.

"The Kremlin has no tools, no mechanisms, to do anything (about the vote)," Shevshenko said.

Alexei II's critics accused him of submitting the church to the dictates of the Kremlin. Former President Vladimir Putin and his successor Dmitry Medvedev were often flanked by the patriarch at occasions of state and the church has been subdued in statements on the war in Chechnya and the state's social failings.

But Alexei II, who was tagged with a KGB codename and accused of collaborating, held an irritating degree of independence in the face of some of the Kremlin's obvious preferences.

He once backed pensioners protesting a change in their allotment and appealed to the state for moderation and an end to the fighting during its war with Georgia in August.

For his part, Kirill has been instrumental in shaping church doctrine, fortified with a sense of the strength of the church's place in society. It enjoys the sympathy of over 70 per cent of the population.

In a particularly nagging piece of church doctrine, Fagan said, in 2000, Kirill played a principal role in drafting a clause that declared the Russian Orthodox Church reserved the right to disobey the state if a conflict arises with their faith.

Against the backdrop of plummeting oil prices, Russia's main export commodity, the rouble slipping far against the dollar and anticipated mass layoffs, analysts say the state is already worried about social unrest.

"If everything goes pear-shaped, Kirill is the only man who could gather wide public support," Fagan said. dpa