"We came into this election with a set coalition, and the electoral law has allotted us a number of seats in the Chamber [of Deputies] and in the Senate which will allow us to govern," Prodi said on Tuesday outside his campaign headquarters in Rome.
Prodi's Union alliance won the weekend elections, taking control of both the chambers of parliament, according to full results released on Tuesday, but Berlusconi has so far refused to concede defeat.
Berlusconi, prime minister since 2001, claimed that "a great many irregularities" might have marred results, and that a pivotal race for six Senate seats - representing Italians living abroad - could be invalidated. That vote had swung the upper chamber to Prodi with four of the six seats going his way.
If each side took one house, Berlusconi said, Italy could follow Germany in creating a coalition joining the country's main political opponents.
"I think maybe we should follow the example of some other European countries, like Germany, to see if there is a case for joining forces and governing together," he said.
Berlusconi says there were many
irregularities in the counting
Earlier reports said Berlusconi refused to concede defeat in Italy's general election, saying there were numerous irregularities in the vote-counting.
The prime minister, in his first public comment on the election, said: "We will not hesitate to recognise the political victory of our adversaries, but only after the votes have been legally checked."
Official data released by the interior ministry showed that Prodi's bloc had won majorities in the lower and upper houses of parliament.
However, the count was extremely close with Prodi winning in the lower house by about 25,000 votes out of 38.1 million cast.
Berlusconi told a news conference that Prodi had been "irresponsible" to claim victory in the early hours of Tuesday with the full count not yet finished.
The interior ministry, which oversaw the count, said 1.1 million votes had not been taken into consideration for the lower house because they had been spoilt or left blank.
However, the ministry said in a statement that 43,028 of these annulled ballots were "disputed", indicating that there were doubts over whether they really had been spoilt or not.
"We do not believe that today, as things stand, someone can claim to have won given the [voting] numbers which display many, many, many murky aspects. I would say too many"
Italian prime minister
The prime minister said he wanted those disputed votes reviewed. He also said there were "many irregularities" in votes from Italians living abroad. This foreign vote proved crucial in the Senate, giving Prodi a two-seat advantage over Berlusconi.
"We do not believe that today, as things stand, someone can claim to have won given the [voting] numbers which display many, many, many murky aspects. I would say too many," Berlusconi said.