Brazil and Argentina will this week announce that they are starting preparatory work on a common currency, in a move which could eventually create the world’s second-largest currency bloc.

South America’s two biggest economies will discuss the plan at a summit in Buenos Aires this week and will invite other Latin American nations to join.

The initial focus will be on how a new currency, which Brazil suggests calling the “sur” (south), could boost regional trade and reduce reliance on the US dollar, officials told the Financial Times. It would at first run in parallel with the Brazilian real and Argentine peso.

“There will be . . . a decision to start studying the parameters needed for a common currency, which includes everything from fiscal issues to the size of the economy and the role of central banks,” Argentina’s economy minister Sergio Massa told the Financial Times.

“It would be a study of mechanisms for trade integration,” he added. “I don’t want to create any false expectations . . . it’s the first step on a long road which Latin America must travel.”

Initially a bilateral project, the initiative would be offered to other nations in Latin America. “It is Argentina and Brazil inviting the rest of the region,” the Argentine minister said.

A currency union that covered all of Latin America would represent about 5 per cent of global GDP, the FT estimates. The world’s largest currency union, the euro, encompasses about…