Protesters say the government has failed to live up to poll promises

The protesters arrived in Brasilia after a two-week 200km (125-mile) walk from the city of Goiania, capital of the neighbouring state.

They said they wanted to highlight the government's failure to distribute land and resettle landless peasant families.

Leaders of the movement later met Brazil's president.

The march was the biggest staged by the Landless Rural Workers' Movement (MST).

Nearly all the city's security forces were deployed to police it, Efe news agency quotes Brasilia's security chief Gen Athos Costa as saying.

Wealth gap

MST says the government has failed to live up to its election promises to find homes for 400,000 families by 2006.

Brazil's President Luiz Inacio Lula da Silva, who was elected in 2003, promised to buy disused land and redistribute it to poor families with no home of their own.

The government says it has already settled a little over a quarter of its target, but MST says the real figure is much lower.

In two years and a half since coming to power, President Lula's government has only managed to find homes for some 80,000 families, according to Efe.

MST leaders met President Lula and presented him with a list of 16 demands including economic reform, increased public spending and meeting the government's pledge on housing.

Leaders of the leftwing movement say they still back the president but analysts say they could withdraw their support for the president's re-election bid if he fails to spend more on resettling landless families.

"We have no doubt that Lula is our friend. We don't want to break with him. We have to change his economic policies," march coordinator Marina Dos Santos told Reuters.

Brazil has one of the biggest wealth gaps in the world. Nearly half of all farmland is owned by just 1% of the population.