Hard line Philippines president Rodrigo Duterte has branded European lawmakers 'crazies' for questioning his deadly war on drugs.

The 71-year-old spoke in English as he asked 'why do you have to f**k with us?' after the European Parliament passed a resolution condemning 'the high number of extrajudicial killings' in his war on drugs.

Duterte fired his broadside in a late-night speech Sunday in Myanmar and vowed again that all traffickers in his country will be killed.

'I don't get these crazies. Why are you trying to impose on us? Why don't you mind your own business,' said Duterte, who frequently uses swear words and other abusive language against his critics.

Hard line Philippines president Rodrigo Duterte (pictured) has branded European lawmakers 'crazies' for questioning his deadly war on drugs

Since taking office in the middle of last year Duterte has overseen a ruthless campaign to eradicate illegal drugs which he says are threatening to turn the Philippines into a narco-state.

Police have reported killing more than 2,500 people, while rights groups say there have been more than 5,000 other deaths linked to the drug war.

Amnesty International and Human Rights Watch have said Duterte may be overseeing crimes against humanity, with police allegedly running anonymous death squads.

Duterte has insisted he has not asked his security forces to break the law, although on other occasions he has called for millions of addicts to be killed and vowed to pardon police officers found guilty of murder.

At the speech to a gathering of the Filipino community in Myanmar's capital Naypyidaw, Duterte warned that many more people would be killed in his drugs crackdown.

'More people will die. I said I will not stop. I will continue until the last drug lord in the Philippines is killed and the pushers (are) out of the streets,' he said.

Reacting to criticism that the operation targeted the poor, Duterte said he must 'destroy' small-time street peddlers as well as the big-time drug lords.

In its resolution, the European lawmakers also called on the UN Human Rights Council to launch a probe into Duterte's drug war, and expressed 'deep alarm' at his plans to bring back the death penalty.

Duterte insisted foreign critics did not understand the Philippines.

The 71-year-old spoke in English as he asked 'why do you have to f**k with us?' after the European Parliament passed a resolution condemning 'the high number of extrajudicial killings' in his war on drugs

To illustrate his theory on the clash of cultures, Duterte referred to a recent Time magazine cover article on gender and sexuality and compared it with what he insisted was blanket Filipino opposition to same-sex marriage.

'That's their culture. It does not apply to us. We are Catholics and there is the civil code which says that you can only marry a woman for me (and) for a woman to marry a man,' he said.

'You stay where God assigned you. Do not mix us all up.'

Duterte insisted he would not be cowed by warnings from foreigners that he may face prosecution over his drug war.

He boasted about calling then-US president Barack Obama a 'son of a whore' last year in response to criticism of the killings, as he repeated his unsubstantiated allegation that the US Central Intelligence Agency was plotting to kill him.

'They miscalculated me. They thought they would scare me with a jail threat and then they would put Obama in front of me. I told them, 'What is it to you?'' Duterte said.

'Now I am even famous because I called their leaders sons of whores, you are all sons of whores.'

Duterte was set to meet Myanmar's de facto leader Aung San Suu Kyi on Monday afternoon, before having high tea with the army's commander-in-chief, Min Aung Hlaing.

His visit coincided with the 60th anniversary of ties between the two countries. Duterte will head to Thailand on Monday evening.