Italian Prime Minister Giuseppe Conte urged a rethink.
"I believe that everyone will eventually realise even in those countries that a shared, orderly, strong and rapid European response is the only solution," he told Spain's La Sexta television. "A slow response would be a useless response."
The opposition League, Italy's most popular party, has struggled to gain much attention during the coronavirus crisis, and has leapt on the EU debate to gain greater traction.
"Commission president von der Leyen has apologised today to Italy and Italians. She could have thought of this sooner. From Europe, all we are getting are words and smoke: zero substance," League leader Matteo Salvini wrote on Twitter.
The party's economic adviser, Claudio Borghi, posted on Twitter a fascist-era poster from World War Two of a smiling Nazi soldier with the slogan "Germany really is your friend".
"Time passes but the tactics are always the same," Borghi wrote.
Von der Leyen told La Repubblica that the European Union would allocate up to 100 billion euros ($109.62 billion) to the hardest-hit countries, starting with Italy, to help cover the cost of lost wages and to preserve jobs.
She said the commission also wanted to make sure that "every euro still available in the EU's annual budget" is spent on tackling the coronavirus crisis.
However, she did not mention the euro bonds sought by Rome.
Underscoring the scale of the epidemic in Italy, the crematorium in the country's financial capital Milan announced on Thursday that it would not take in any more bodies for the rest of April to allow it to clear its backlog of coffins.
