The leaders of Brazil, Bolivia, Venezuela and Argentina reached the agreement at an emergency summit in the Argentine town of Puerto Iguazu on Thursday after Bolivia nationalised its natural gas industry.
The leaders stressed the idea of regional unity and dismissed the notion of a rift between Bolivia and Venezuela on one side and Brazil and Argentina - Bolivia's top gas markets - on the other.
Luiz Inacio Lula da Silva, the Brazilian president, said at the meeting's closing news conference that he saw no alliance between Bolivia and Venezuela.
After three hours of talks, they came up with a document spelling out the way forward.
Nestor Kirchner, the president of Argentina, said: "In terms of price, the document is absolutely clear. It says ... that bilateral meetings will be the means to resolve price discussion between countries."
The document also said it was important to keep gas supplies on line.
Evo Morales, the president of Bolivia, decreed a state takeover of the country's oil and gas industries on Monday, giving government energy company YPFB control over production and the state a 51% stake in several foreign energy companies.
On Thursday Morales met his ally, Hugo Chavez, the president of Venezuela, who backs the move.
Morales has ordered a takeover
of Bolivia's oil and gas industries
Brazil and Argentina have relied on cheap imports from Bolivia and their leaders are worried about a rise in prices from the nationalisation that could hurt their standing at home as they run for re-election.
Morales's move also angered some business leaders in neighbouring Brazil, whose state oil company Petrobras is the largest investor in Bolivian energy with $1.5 billion in investments.
The Bolivian president has given foreign companies six months to sign new contracts or face possible expulsion, accusing them of exploiting the country's natural resources to little benefit for ordinary Bolivians.