MANILA — Philippine President Rodrigo Duterte warned on Thursday he may impose martial law and suspend elections for tens of thousands of local posts, fuelling concerns about democracy under his rule.

Duterte said he was considering both measures as part of his controversial campaign to eradicate illegal drugs in society, and that martial law would solve a range of other security threats.

"If I declare martial law, I will finish all the problems, not just drugs," Duterte told reporters in a pre-dawn briefing after returning from neighbouring Thailand, which is under military rule.

Duterte said that, as part of martial law, he may create military courts to hear cases against terrorists.

"I will allow the military to try you and put you to death by hanging," he said, referring to Islamic militants in the south of the country.

Since easily winning presidential elections last year and taking office nine months ago, Duterte has given conflicting statements on whether he intended to impose military rule.

The issue is highly sensitive in the Philippines, which is still trying to build a strong democracy three decades after a famous "People Power" revolution ended Ferdinand Marcos’s dictatorship.

Duterte has previously warned he would be prepared to defy constitutional safeguards and restrictions on martial law, although he and his aides have later sought to downplay those threats.

On Thursday he gave an emphatic case for martial law, saying it would stop the Philippines from "exploding".

"I will be harsh," Duterte said as he described his approach to military rule.

’Narco-politics’

Duterte also said he was planning to appoint leaders of more than 42,000 districts, known as barangays, across the nation instead of having them elected in polls that were scheduled for October.

"We are looking for a way to just appoint the barangay captains," Duterte said, adding this was necessary because 40 per cent of them were involved in drug trafficking.

"Narco-politics has entered the mainstream of Philippine politics."

The elections, which by law should be held every three years, are important to the Philippines’ democracy because the barangays are the smallest government unit responsible for a wide range of local services.

Barangay officials also help to monitor communities for illegal drugs and draw up the lists of traffickers or addicts. Police use those lists for raids that frequently lead to suspects being killed.

Duterte won the presidential elections after promising during the campaign to eradicate drugs in society by killing tens of thousands of criminals.

Police have reported killing nearly 2,600 people in his drug war while rights groups say thousands more have been killed.

Local opponents have said they are planning to file a case against Duterte with the International Criminal Court, and a lawmaker last week filed an impeachment complaint against him in Congress. — AFP