BOGOTA (Reuters) - World tennis No.1 Martina Hingis ventured Thursday into a Bogota shantytown -- a hotbed of violent crime and Marxist rebels -- to champion the fight against world poverty and help armies of street kids.

Swiss ace Hingis flew into the Colombian capital late Wednesday as part of a new United Nations Development Program (UNDP) campaign called ``Teams To End Poverty,'' backed also by Brazilian soccer star Ronaldo, actors Omar Sharif and Gerard Depardieu and a handful of supermodels.

Hingis, 19, opted to focus her attention on street children after seeing a low-budget movie entitled ``The Rose Seller,'' which graphically depicts young drug addicts, child prostitutes and juvenile delinquents on Colombia's toughest streets.

The first stop on the day-long tour was Ciudad Bolivar, a sprawling neighborhood of shacks, many built from tin and cardboard, spread across hills on the southern edge of Bogota.

Hingis left her hotel in an upscale district of the capital amid tight security, traveling in a minibus backed by at least 20 armor-plated trucks full of state security police and special forces units armed with automatic assault rifles.

``I've never been to South America before. I'm looking at all these programs ... and to see how life is on the streets,'' Hingis told Reuters.

``The UNDP program has many elements and I think street children is one of the most needed because children are the future,'' she added.

Ciudad Bolivar is one of the capital's poorest neighborhoods -- refuge to thousands of families displaced by Colombia's long-running internal conflict, a stronghold for urban communist guerrillas and home to many of the city's estimated 7,000 street kids.

Up to 30,000 children have been abandoned on Colombia's streets nationwide, according to the office of the government's Human Rights Ombudsman.

Hingis was set to visit a project to help some of Colombia's estimated 25,000 child prostitutes later in the day. She was due to be accompanied by Leidy Tabares, the young protagonist of ``The Rose Seller,'' who was plucked off the streets of the northwest city of Medellin to star in the film.

WAR ON POVERTY

Hingis, born in Slovakia before moving with her family to Switzerland, is one of the world's richest sportswomen. She recently told a U.S. tennis magazine that she had $12 million in the bank.

The trip to the hemisphere's most violent nation marks her first assignment for the UNDP campaign, which aims to reduce the number of people living in absolute poverty across the world from 1.2 billion at present to half that by 2015.

The campaign does not focus just on street children but on all aspects of poverty including access to education, water, health care and women's rights.

``The world has sufficient wealth to allow everybody to live in dignity. ... If we don't stop poverty it means we agree with the fact that a child is dying every three seconds somewhere in the world to pay for our bad social organization,'' said Jean Fabre, Geneva-based deputy director of the UNDP.

Fabre said UNDP statistics showed one person in five in the world lived in misery and 50 percent of the world's population was poor. The Colombian government estimates that 55 percent of its 40 million population live in poverty, including at least 5.5 million children -- about one-third of all Colombians under the age of 18.

According to the government's Human Rights Ombudsman, more than 25,000 Colombian children under the age of 18 work as prostitutes -- a 600 percent increase over 12 years ago.

Last year, more than 1,800 children were murdered in Colombia, where a total of some 25,000 homicides were reported, according to the ombudsman's statistics.