(AFP) - Crisis-wracked Democratic Republic of Congo was bracing for fresh unrest Sunday after the country's influential Catholic church vowed to defy a protest ban and hold a "peaceful march" to urge implementation of a deal for President Joseph Kabila to leave office.

Kabila, who march organisers are calling on to say he will not stand for a third term, has been in power since 2001 when he succeeded his assassinated father Laurent Kabila.

He refused to step down at the end of his second and final term in December 2016.

That refusal led to protests and a bloody crackdown. Demonstrations have been banned or else widely repressed since September 2016 but several have nonetheless gone ahead since with many ending in bloodshed.

The church's call for a new rally despite authorities bluntly saying it should not proceed saw some observers warn of renewed unrest.

"The demonstrations tomorrow (Sunday) in the Congo could be the largest since last year," tweeted analyst Jason Stearns, a DR Congo expert at New York University's Center on International Cooperation.

"All major opposition parties, civil society, youth movements, and the Catholic Church have all backed peaceful demonstrations," Stearns added.

Elections were due to take place by the end of this year under a church-mediated deal aimed at avoiding more violence in a vast, mineral-rich country which has never had a peaceful transition of power since independence from Belgium in 1960.

After multiple postponements -- officially due to violence in the Kasai region -- the delayed poll is now scheduled for December 23 next year.

- Bibles in hand -

About 150 Catholic churches have urged believers to heed their call to protest, bibles and crucifixes in hand, Sunday in the capital Kinshasa to demand implementation of a deal signed exactly a year ago and designed to restore stability with Kabila stepping down.

Neither the National Episcopal Conference nor the country's Vatican representative have commented on the planned rally.

But the governor of the city of 10 million Saturday stated the unauthorised march cannot proceed.

"The city does not have sufficient numbers of police officers to supervise this march," Andre Kimbuta said. "Therefore, I do not recognise the authorisation requested."

March spokeswoman Leonie Kandolo insisted, however, that "lay people will march tomorrow (and) the city authority and the police must fulfil their role of protecting people and property."

- 'Destiny' -

March organisers have asked worshippers to gather after morning mass and "take our destiny in hand -- our beautiful country is suffering."

Clinging on to power, Kabila is banned by the constitution from running for a third term, but the deal allows him to stay on until the next poll is held.

The opposition has complained in recent days that new electoral reforms "automatically" ban certain hopefuls from next year's poll by setting a minimum vote share threshold a candidate must win to obtain a seat as well as demanding a deposit equivalent to several hundred dollars.

Recent days have seen three pro-democracy activists released after spending five months in prison for organising "an anarchic march" in the country's second-largest city Lubumbashi.

But another dozen anti-Kabila activists from the Struggle for Change movement were arrested Friday after a sit-down protest near the southern city of Kananga.

© Agence France-Presse