Protesters erected flaming barricades and threw rocks at police in the streets of Haiti's capital as angry demonstrations against the rising cost of living virtually paralysed the city.

Businesses were shuttered, schools were closed and many Port-au-Prince residents stayed inside as the demonstrations that began last Wednesday in the southern city of Les Cayes gripped the teeming capital of the Caribbean nation of nearly nine million people.

There were no immediate reports of deaths or injuries in the latest protests.

Five people have been killed in a week of demonstrations over high food prices in the poorest country in the Americas. A man died in gunfire on Monday and four others were killed during a riot last week in Les Cayes, when an angry mob looted a food warehouse and UN peacekeepers were attacked.

In response to the unrest, the government of President Rene Preval, whose 2006 election brought a measure of calm to a nation roiled by decades of political upheaval, announced a multimillion-dollar package of economic investments aimed at lowering the cost of living.

Government officials were huddled in meetings on Tuesday to determine what to do about the growing unrest, the worst to hit the nation since Preval took office.

Rock-throwing protesters gathered in front of the National Palace Tuesday as demonstrators in other parts of the sprawling city dragged wrecked cars into intersections and set piles of tyres on fire.

On Monday, the UN World Food Program warned that surging food prices around the world could lead to increased tensions like those seen in Haiti.

The agency said unrest related to living costs had already hit Burkina Faso, Cameroon, Egypt, Indonesia, Ivory Coast, Mauritania, Mozambique and Senegal.