Incoming Philippine president Rodrigo Duterte pledged Thursday to spread economic activity beyond the overpopulated capital of Manila, calling it a "dead" city overrun by shantytowns.

Duterte said he would create new jobs by setting up economic zones outside of Manila to spread the wealth beyond the sprawling metropolis of about 15 million people, and that he would not allow any more factories to be built in the capital.

"I have to create more jobs but Manila is already saturated," Duterte told reporters in the southern city of Davao, which he has ruled as mayor for most of the past two decades.

"If there are any investors coming in, I will tell them I will not allow factories anymore in Manila, not only because it is a dead city but because I have to build a new environment for the people."

Duterte, who won a landslide election victory just over two weeks ago, said repeatedly while campaigning one of his top priorities would be improving the lives of about 26 million Filipinos, more than a fourth of the population, who live on $1.30 a day or less.

Popular frustrations over the sharp rich-poor divide that largely remain despite years of continuous strong economic growth under incumbent leader Benigno Aquino helped to bring Duterte to power, analysts have said.

Lack of opportunities around the rest of the Philippines have for decades made Manila a magnet for people seeking a better life, but millions have instead been forced to live miserable existences in mega-slums.

The nation's rich-poor divide is on vivid display in Manila, where the slums are just a few kilometres (miles) from gated villages with luxury homes for the rich, as well as glittering skyscrapers and billion-dollar casino complexes.

Duterte expressed dismay at the sight of Manila's polluted canals, which are surrounded by shantytowns.

Duterte, who will begin a six-year term on June 30, said he wanted to create opportunities elsewhere so people would not have to live in such squalid conditions.

"I will ask the engineers to find land because we will build economic zones there," Duterte said, adding people living in the Manila slums would be moved there.

"I have to relocate them but before I relocate them, I have to establish economic activity."

Manila accounts for more than a third of the economic output of the country, with two surrounding regions contributing another quarter, according to official data.