People in the slums of Manila are living in fear after new Philippines President Rodrigo Duterte called on police and vigilantes to kill drug suspects.

Key points: Around 500 people have been killed since Rodrigo Duterte declared war on crime

Around 500 people have been killed since Rodrigo Duterte declared war on crime The policy is popular in the nation which has a major drug and crime problem

The policy is popular in the nation which has a major drug and crime problem But the families of victims say police claims they were shot while resisting arrest don't stack up

The ABC recently spent five days in the Philippines, during which time around 50 suspects were killed, mostly while allegedly resisting arrest.

In Tondo, a Manila slum, the ABC visited the family of one man who had been shot by police while in custody.

Roland Resido was arrested at his home, then taken away in handcuffs. He was one of three suspects shot dead in custody by Tondo police on July 6.

"We arrested three guys and brought them in to get tested," local police commander, Inspector Monico Aliado, told the ABC.

"They grabbed an officer's gun. There wasn't anything our officers could do except defend themselves."

Mr Resido's family disputes this version of events.

"He was supposed to be taken to the precinct, and he went with them willingly," his widow Marissa Resido said.

"I did not realise this is what they will do to him."

Mr Resido's son, JR, said: "That is just a show that the police said that he fought them, so that's why they killed him.

"He was in handcuffs. How can he fight when his hands were handcuffed?"

'Police are on a killing spree'

People walking into a mass oath-taking of "drug personalities" in Tondo in the Philippines. ( ABC News: Adam Harvey )

One month into Mr Duterte's six-year presidency, around 500 drug suspects have been executed. Police are responsible for many of the killings.

One of the very few Filipinos prepared to speak out about the extra-judicial killings is Catholic priest Father Amado Picardal.

"I think there is more to come, because the reign of terror has started. The police are on a killing spree, and so are the vigilante groups," he said.

Catholic priest Father Amado Picardal has spoken out against President Rodrigo Duterte. ( ABC News )

Father Picardal worked in Davao City, where human rights groups say about 1,300 criminal suspects were executed by police and death squads over 20 years.

Father Picardal said the killing of suspects was "murder encouraged by the President".

"My worst fears are being realised, but even I did not think it would begin so quickly," Father Picardal said.

"The way I see it is that they want to make an example, so the addicts are so scared, so intimidated they go to surrender in groups. They have to do a lot of killings to convince others of what they are doing."

Drug users pledge not to reoffend

A crowd of 'surrendered drug personalities' swearing the oath to give up drugs at a mass ceremony in the Philippines. ( ABC News: Adam Harvey )

Tens of thousands of drug users have been forced to "surrender" to police at mass-pledging ceremonies where they promise to give up drugs.

The ABC attended one event in a Manila slum where about 500 people suspected of using crystal methamphetamine — known in the Philippines as shabu — were forced to register as drug criminals and promise not to use again.

Those who don't turn up are sought out in the slums by police and district officials and given final warnings.

The ABC accompanied one patrol through Tondo, where users were visited at their homes. One man, who said he was a user who supported his habit by working as a "runner" for dealers, was told, "This is your warning, let's not wait for it to get worse."

Users are expected to get clean on their own. In Manila the handful of rehab clinics are privately run and cost around $US1,000 a month for in-house treatment. Most Tondo residents earn less than $10 a day.

'Kill him ... I'll give you a medal'

The Manila slum of Tondo. ( ABC News: Adam Harvey )

There is no need to directly threaten Tondo's drug suspects with the prospect of being killed if they don't reform — the president is doing that himself at public events.

"Rehab is no longer an option," Mr Duterte told a cheering audience in his home town of Davao City.

"So those of you in your neighbourhood, feel free to call us, the police, or do it yourself if you have a gun. You have my support."

In one rally, Mr Duterte told police in the crowd: "In an arrest, you must overcome the resistance of the criminal. You must really overcome it. And if he fights, and he fights to death, you can kill him ... Then I'll give you a medal."