Philippine President Rodrigo Duterte yesterday defended his brutal war against drugs in a speech to almost 7,000 Filipinos who gathered at the Singapore Expo.

"My campaign against drugs will not stop until the end of my term... until the last pusher and last drug lord (is killed)," said the President as he wrapped up his two-day state visit to Singapore.

Mr Duterte won his country's general election in May largely on an anti-crime platform. Since taking office in June, more than 2,000 people have died in anti-drug operations, while more than 3,000 others have been killed in unexplained circumstances, official figures show.

The campaign has been criticised by the United States and the international community for violating human rights. But Mr Duterte yesterday brought out a thick pile of papers listing suspects in the illegal drug industry, saying the scale of the problem merited the response.

The President received a boisterous welcome from those present at the Max Pavilion and Hall 9, as he spoke in a mix of English, Filipino and his local Visayan dialect.

At the start of his speech, Mr Duterte thanked Singapore for hosting more than 180,000 Filipinos and for its good treatment of those working here. "I have to thank first the Republic of Singapore for... giving them the opportunity to work and earn money here and for treating my countrymen the way you... (do) ordinary Singaporean citizens. It is almost being equal here."

Earlier in the day, Mr Duterte was hosted by Prime Minister Lee Hsien Loong to lunch at The Coconut Club, an eatery in Ann Siang Hill known for its nasi lemak.

Mr Duterte and Philippine Trade and Industry Secretary Ramon Lopez then met Singapore business leaders to discuss trade and investment opportunities.

Mr Duterte also visited the Singapore Botanic Gardens, where he had an orchid, the Dendrobium Rodrigo Roa Duterte, named after him, a traditional honour for visiting foreign leaders.