Letta's comments came Friday at a press conference following a European Union event in Vilnius, Lithuania, The Wall Street Journal reported.
"I'm sure that the new confidence vote will make us stronger," Letta said, adding he would ask Italian President Giorgio Napolitano Monday to call the confidence vote after Dec. 8.
Forza Italia, headed by former Italian Prime Minister Silvio Berlusconi, withdrew its support for a bipartisan coalition in the Parliament on Tuesday and voted against the 2014 budget law, Italy's ANSA news agency reported.
The move came after Letta's Democratic Party insisted Berlusconi be kicked out of the Senate as a result of his tax-fraud conviction.
Forza Italia and the New Center Right party, led by Deputy Premier Angelino Alfano, said they will join forces for the next election.