A senior Catholic archbishop yesterday called for Filipinos to choose peace over violence and end a spate of drug-related killings that have divided the nation.

Archbishop Socrates Villegas, president of the Catholic Bishops' Conference of the Philippines, was speaking as the Church launched a new prayer campaign to 'heal the nation and stop the killings' in the country.

Philippine Catholic bishops have been stepping up opposition to killings blamed on a government crack-down on drugs.

They are now asking the faithful to pray with the rosary for 33 days until December 8, an important Catholic feast of the Immaculate Conception.

The new campaign follows the 40-day ringing of church bells and lighting of candles for thousands of people killed in President Rodrigo Duterte's 16-month war on drugs.

More than 3,900 Filipinos have been killed in what the police called self-defence after armed suspects resisted arrest. Critics dispute that and say executions are taking place, with zero accountability, in allegations the police reject.

In a mass for families of victims of drug-related killings, Villegas said that if the killings continue 'a curse awaits a nation that kills its own people'.

Symbolically, the mass was held at the Catholic shrine of Mary Queen of Peace which stands on the site where nuns stopped soldiers from attacking mutineers who overthrew dictator Ferdinand Marcos in 1986.

'Why do we applaud the killings?' Villegas asked in his homily. 'We chose violence instead of peace. We chose lies instead of truth. We chose to laugh at obscenities instead of correcting these. We chose to be silent than to be involved.'

Human rights lawyers, politicians, civil society groups and opponents of the president joined the families of victims in a religious procession after the mass to the 'People Power' monument, where they held a cultural show.

Harry Roque, presidential spokesman, said the government welcomed 'constructive dissent' after hundreds joined the religious activity condemning the killings.

'We reiterate that this administration does not - and will never - condone extrajudicial and vigilante killings,' Roque, a human rights lawyer, said in a statement, adding that police have been investigating more than 2,200 killings with drug-related motives.

'Accountability is essential to good government. The president himself made a clear stance that any violation committed by the police during operations would be dealt with accordingly.'

Roque asked Catholic bishops to work closely with government on drug rehabilitation and its anti-drug campaign.

According to local outlet SunStar, Roque stressed that the government and the Church should not clash with each other but instead should be united in addressing the country's problems.

'It's better to have come to terms on the part of the Church and the government. We are both looking forward to upholding the morality and the rights of our countrymen,' Roque said. 'I don't think there should be a conflict. From now on, I think, what I have been reading from the President himself is that he's exerting all efforts to have complete conciliation with the Church and all religious groups.'

Additional reporting by Reuters.