Romano Prodi looks set to be confirmed as the winner of Italy's general election after the number of contested ballots was drastically lowered.
Vote checking is continuing four days after polls closed on Monday
The interior ministry said it had made an error and only 5,000 votes were being checked, instead of about 80,000.
However, Prime Minister Silvio Berlusconi has told supporters in Rome he is "carrying on" and will "resist".
Our correspondent says even if all the contested ballots went to Mr Berlusconi the final result would not change.
Mr Berlusconi, who heads a centre-right coalition, had called for a review of votes, claiming there had been irregularities.
He had refused to concede to his centre-left rival until all final checks are made.
He voiced concern over more than a million spoilt and blank ballots in the election, and said there had been "much fraud" in the poll, held on Sunday and Monday.
It was initially announced that 43,028 ballots were being checked for the Chamber of Deputies (lower house) and 39,822 for the Senate (upper house).
But the interior ministry said on Friday that "the first provisional calculation of contested ballots was the result of a material error".
The correct amounts being counted were 2,131 and 3,135 respectively, it said.
Mr Berlusconi has insisted the situation is stalled.
""We are at a standstill," he wrote in a letter to be published in Italian daily Corriere della Sera on Saturday.
Supreme Court ruling
Mr Prodi has claimed victory in the polls, after official results showed he had won just enough seats to control the Senate (upper house) after having already won a lower house majority.
The count gave Mr Prodi 158 Senate seats, against 156 for Mr Berlusconi.
He won the lower house by about 25,000 votes.
Regional party officials quoted in the Italian press say disputed ballots are being allocated equally to each side in roughly the same proportions as in the overall vote.
The BBC's David Willey in Rome says the lower number of contested ballots means the official result cannot now be switched back to a win for Mr Berlusconi.
Following the review of contested ballots, the provincial courts will routinely double-check the official written reports from all 60,000 polling stations, to ensure their vote tally corresponds to the results that local election officials reported by phone to the interior ministry.
Mr Berlusconi also alleged irregularities in the vote for the Senate - which was swung in Mr Prodi's favour by Italians voting abroad.
However, such was the margin in Mr Prodi's favour in the foreign constituencies, that correspondents say it seems unlikely any check can overturn the outcome.
The results are considered provisional until Italy's supreme court, the Corte di Cassazione, rules on their validity. This is expected to happen next week.