AUGUSTA — An investigation into allegations of voter fraud has turned up no cases of blatant wrongdoing, but Maine’s top election official said Wednesday it does point to a need to overhaul an election model that dates back to the state’s origins.

“Our election system is long overdue for a comprehensive reexamination of our methodologies and ways in which we govern our elections,” Secretary of State Charlie Summers said during a news conference in his office. “We’re still operating on an 1820 law, but this is 2011.”

While his probe turned up no hard pattern of fraud and one 9-year-old case of a non-citizen voting, it showed a system that’s “incredibly vulnerable” to fraud, said Summers. One example, he said, is a state requirement to keep voting records only two years.

Another weakness, Summers said, is the lack of a single definition of residency. He said several definitions are spread through the state’s statutes. Summers said he will develop reforms for the Legislature to consider when it returns in January.

The investigation was requested nearly two months ago by state Republican Chairman Charles Webster, just as a “people’s veto” referendum campaign to restore Maine’s election-day registration system and repeal a law requiring two days’ wait began to heat up.

Webster and other Republicans have maintained that same-day registration opens the door to widespread fraud and abuse, and that the two business days’ wait would give election clerks time to weed out would-be voters who seek to cast ballots in Maine. Webster said he’d uncovered more than 200 cases of possible election fraud, mainly among students attending state universities.

“Secretary Summers has demonstrated that Charlie Webster’s allegations against those 206 students were false, were outrageous, and perhaps were defamatory,” said David Farmer, spokesman for Protect Maine Votes, which is leading the campaign supporting the repeal. “That’s really inexcusable and it shows a pattern of trying to scare students into not voting.”

Webster said Summers’ findings underscore the need to give local election officials more time to examine registrations so they can spot ineligible voters.

“Without a period of time for town clerks to do their work, a lot of things can happen,” said Webster.

Summers said that of all of the students, five were found to have voted in Maine and another state in the same year — but not in the same election, while 44 were registered in Maine but not their “home” state. Nearly a dozen students left the “previous address” question blank, so their registrations should have been thrown out.

In all, Summers’ office checked a sampling of 428 names, a small fraction of 1 percent of the more than 972,000 voters listed in Maine’s Central Voter Registration System. Of all cases suggesting potential fraud, 84 percent were due to clerical errors, most of which occurred on Election Day, the secretary said.

The sampling of 428 names on the central voter list showed just over 1 percent to be non-citizens. Only one of the non-citizens was confirmed to have registered and voted in Maine, and that was in 2002. That person has since left the United States, Summers said.