At a news conference to present the results of the negotiating marathon, Centeno and the European commissioner for economic affairs, Pierre Moscovici, acknowledged that "more work is still needed", while hailing what they called the "small steps" now taken, which they said should not be downplayed but had mostly "symbolic importance".

Noting that euro-zone finance ministers had established "very clearly a series of principles that will guide the budgetary instrument," Mário Centeno, the Eurogroup president and Portugal’s finance minister, acknowledged that "more work is needed on some issues" such as the overall size of this budget and its funding – which are to be dealt with as part of discussions of the European Union's multiyear budget later this year.

"When we talk about a budget, size matters, and this will be decided by the leaders more at the end of the year,” Centeno said. “There is work ahead in the question of the dimension of the financial envelope of this instrument. Sources of funding also require more work.”

He maintained, though, that the agreement represents "a step forward ".

Moscovici also acknowledged that "there is still plenty of ground to cover", because "there were many aspects, namely funding" left open. However, he said that in the current context "it is the best compromise possible", given that "several ministers from several countries before were adamantly opposed to the simple principle of a budget for the euro area.

"Let's not underestimate the symbolic importance of this step, although the work is not yet closed," he said.