In meetings and dialogue, participants are to develop alternatives to the march of free-trade globalization they say favors rich nations and threatens the world's poor.

A host of seminars is planned to develop strategy that goes beyond one-time protests such as the massive and destructive demonstration that hit Seattle in 1999 during a meeting of the World Trade Organization.

It is possible "to bring several hundred disparate organizations together to reflect on alternative proposals through dialogue," said forum coordinator Candido Grzybowski.

Under the slogan "changing the world is possible," the forum seeks to tackle the world economy, the September 11 terrorist attacks on the United States, the Argentine economic crisis and world peace.

"The shipwreck of Argentina is a real example of the ravages of economic liberalization," said Bernard Cassen, whose association favors a world tax on financial transations to help the poor.

Argentina declared the biggest default in history last month, suspending payments on its massive foreign debt after nearly four years of recession.

The star of the Porto Alegre forum, taking place as business and financial leaders convene in New York for the World Economic Forum starting Thursday, is French activist Jose Bove.

He said the Porto Alegre gathering, now in its second-straight year, had established its legitimacy in drawing a great number of politicians to Brazil.

"Nowadays it is the politicians who are asking to understand," said Bove, who founded a French anti-globalization group that last year joined a march by activists that culminated in the destruction of genetically modified products in a laboratory south of Porto Alegre owned by US agribusiness giant Monsanto.

Security was boosted this year amid fears of street violence and reports of death threats received by members of the leftist Brazilian Workers' party.

Military Police Colonel Ilson de Oliveira said the police presence would be four times the size of last year, and deputy state governor Miguel Rossetto warned there would be zero tolerance for violence of any kind.

Porto Alegre Mayor Tarso Genro, in a joint press conference Tuesday with Spanish judge Baltasar Garzon, said the forum had rejected requests from groups with terrorist links who sought to participate, including the Basque separatist group ETA.