The MST has been carrying out farm invasions

Their 180-kilometre (112-mile) march to Brasilia is in support of plans to settle one million landless families over the next four years.

The government's National Land Reform Programme will soon be presented to President Luiz Inacio Lula da Silva.

The peasants, who set out eight days ago, are demanding to meet the president on Thursday to back the plan.

'Historic problems'

Lula's Workers' Party, which leads the governing coalition, has always had a close relationship with the Landless Movement (MST).

However, the MST has recently been invading farms and imposing blockades to try to force the government to adhere to its election promises of land reform.

Earlier this month, MST's leader Jose Valdir Miesnerovicz told the BBC that a national land reform plan was needed to resolve Brazil's "historic problems" of concentration of land ownership, unemployment and poverty.

He said the MST march was not intended as a protest against Lula's government, and added that he hoped the movement could help the government implement its plan.

Correspondents say land distribution in Brazil is among the most uneven in the world, with 20% of the population owning 90% of farmland and the poorest 40% owning just 1% of the land.