Just a month into his presidency, Duterte used his inaugural State of the Nation Address to warn the public to steer clear of drug use, the scale of which was "staggering and scary" and promised no relenting in his crackdown.

Nicknamed "the punisher" and "Duterte Harry" for his brutal fight against crime, Duterte hit back at activists incensed by a surge in the killing of suspected drug traffickers, saying human rights should protect dignity, not let criminals destroy the country.

"There will be no let up in this campaign. Double your efforts. Triple them if need be," Duterte said in a message in support of the police in his speech to a joint legislative session.

"We will not stop until the last drug lord, the last financier and the last pusher have surrendered or put behind bars. Or below the ground if they so wish."

Duterte did not mention the number of suspected drugs dealers killed during his efforts but police have logged 240 deaths related to the trade since he took office, although other estimates are higher.

He said 120,000 people had surrendered to police in the past month, and 70,000 were drug pushers.

"The sheer number and problem will drown us," he said.

Duterte was swept to power in May on a wave of public anti-establishment frustration over crime and poverty, winning 16 million votes and an approval rating of 91 percent, one of the highest recorded in the Philippines.