Brazilian President Luiz Inacio Lula da Silva has called for increased economic, cultural and social integration of South American countries as he opened a summit with a dozen leaders of the region in Brasilia.

"Today we are taking the first steps to resume our dialogue," he told the meeting on Tuesday attended by all the region's leaders except Peru.

Lula urged state banks to work together to finance development and said the region should reduce dependence on "extra-regional currencies" for trade, without mentioning the US dollar.

He proposed creating a regional energy market and suggested coordinated actions to tackle climate crisis.

Lula said South American integration was interrupted in recent years by conservative governments, singling out his far-right predecessor Jair Bolsonaro who, he said, led to the isolation of Brazil from the world and its neighbours.

Ideological divisions

Ideological divisions undermined a previous attempt at regional cooperation called Unasur created by leftist presidents in 2008 that floundered when several countries elected right-wing governments, creating diplomatic fissures on the continent.

Tuesday's meeting included Venezuelan President Nicolas Maduro, who met with Lula on Monday on his first visit to Brazil in eight years to fully restore relations that were broken off by Bolsonaro.

Maduro is hoping the South American countries will unite in calling on the United States to lift its sanctions against Venezuela, which he and Lula assailed for exacerbating the humanitarian crisis in the country at their news conference.

The White House and US State Department did not immediately respond to a request for comment on the criticism of sanctions against Venezuela.

Lula's embrace of Maduro, criticised by the United States as an authoritarian leader, met with sharp comment from some foreign policy analysts and the opposition in Brasilia.

Oliver Stuenkel of the Getulio Vargas think tank in Sao Paulo said it was "damaging to Brazil's international reputation."

The PT, Lula's Worker's Party, pushed back on the critiques.

Camila Moreno, a member of the PT national executive committee, said the responses to Maduro's visit to Brazil with other heads of states as part of an "imperialist discourse."

"Anyone who has studied even a little bit about international relations knows that having relations with the neighbouring countries is important for us. For the protection of the environment, for commercial relations and to combat organised crime," she wrote on Twitter.