Barroso insisted that such duties fall to the commission, the European Union's executive arm.
"The Commission is the economic government of the Union. For this, we certainly don't need more institutions," Barroso said in a speech at the European parliament in Strasbourg.
Europe needs "more than ever the independent authority of the commission," he said, adding that Brussels was "the guarantor of fairness."
Last month, French President Nicolas Sarkozy and German Chancellor Angela Merkel proposed the creation of an economic government to guide national policies in the 17-nation eurozone.
They said EU president Herman Van Rompuy, who already chairs the council of 27 EU states, could take the helm of this new eurozone institution.
The commission fears that the proposal would sideline it from the decision-making process.