Heavy voter turnout caused long lines at polling locations across New Jersey, and state officials reported an "extraordinarily" high number of voters being turned away because of registration problems.
The state Public Advocate's Office said many voters were being turned away from the polls because they were told they aren't registered.
Spokeswoman Laurie Facciarossa said voters who believe they are in the state's registration database but not yet in a poll book should be given a provisional ballot, which will be counted after their registration can be verified.
She urged those who are unsure to go to their local county elections office to see if they're in the database, or to see a judge at a county courthouse. Both locations will remain open at least until polls close at 8 p.m.
By 2 p.m., Facciarossa said, her office had represented about 250 who believed they had been wrongly turned away. Judges allowed 225 of them to vote.
Several other agencies and voter advocate groups represented additional voters.
"If you believe you're properly registered in the state of New Jersey, do not walk away from the chance to vote in this historic election," she said. "There are armies of people standing behind you, working to ensure that you have the opportunity to exercise your right to vote."
In addition to voter registration problems, Facciarossa said the Public Advocate was fighting an attempt to disqualify 24 absentee ballots cast by patients at the Trenton Psychiatric Hospital in Mercer County.
The Public Advocate's Office is just one of many state agencies, including the U.S. Attorney's office and the New Jersey Attorney General's office, as well as partisan organizations that have dispatched lawyers across the state to help voters who may have been left off the books.
The problems are a result of an onslaught of new voter registrations. Of a record 5.4 million residents registered to vote in Tuesday's election, more than 600,000 came in since January, and county officials were scrambling to update their official voter rolls.
Long lines were reported throughout the state. Officials have said everyone in line by 8 p.m. will be permitted to cast a ballot, even if it delays the scheduled poll closing time.
There also were scattered problems with voting equipment, and a judge rejected a request to extend polling hours in one of New Jersey's largest counties.
In Essex County, 14 machines had to be replaced during voting -- half of them because of problems caused by poll worker error.
Carmine Casciano, the superintendent of elections in Essex County said some poll workers inadvertently turned machines off while they were running because they were unsure how to operate them.
The other machines had to be replaced due to unspecified malfunctions, Casciano said. All polling sites were working properly by early afternoon.
The Obama campaign filed an emergency request that polling hours be extended at three polling places in Newark, where machines had been down for 45 minutes to two hours. A judge rejected the request.
New Jersey Attorney General's spokesman David Wald said the 540 lawyers dispatched around the state by the office to help with elections were mostly dealing with individual court cases of people seeking petitions for the right to vote or contesting why they weren't on voter rolls.
In addition, the U.S. Justice Department was monitoring the elections in Bergen County and Penns Grove in Salem County. The Penns Grove case stems from the settlement of a lawsuit earlier this year to ensure Spanish-speaking voters have equal access to the polls.
The American Civil Liberties Union of New Jersey, which had 175 volunteer monitors on duty, reported that some voters around the state were improperly asked to provide identification to vote.