"As we are polite, we open the little letters from Brussels, we read them, we respond to them. They write back and we respond, but we are not changing a comma of the budget that will lead Italy to growth," Salvini said, as quoted by the ANSA news agency.
He also accused the EU leadership of attempts to hinder Italy's economic growth.
"If Brussels or some big professors want Italy at zero growth, they have run into the wrong government and the wrong minister," he said.
On Tuesday, the European Commission rejected Italy's draft budget for 2019 and gave Rome three weeks to revise it. The same day, Italian Prime Minister Giuseppe Conte said it would be difficult for Rome to change the draft budget substantially, adding that there was "no Plan B." The country's foreign minister, Enzo Moavero Milanesi, also said the government would not revise its budget plan for 2019.