Officials at Boston City Hall haven't seen many new voter registrations in the weeks leading up to this month's preliminary municipal elections, but are bracing for a possible blitz of new voters generated by mayoral hopefuls looking for an advantage in a crowded 12-person field.

The deadline to register to vote in the Sept. 24 preliminary is Wednesday.

Geraldine Cuddyer, chairwoman of the Boston Board of Election Commissioners, told the News Service late last week that her office has not yet seen much of an increase in registrations since the mayoral race has been in full swing. "There has not been an uptick we have seen," Cuddyer said.

Cuddyer does expect things to get busier as election day nears. She's reached out to the campaigns to ask for cooperation in coexisting outside polling stations and with registration drives. Cuddyer said 3,479 new registrations or alterations have been received so far, which she described as "not a lot."

"The deadline is not flexible and that's what I tell them. It's not a suggestion," Cuddyer said.

One problem registration drives may encounter is the tight timeframe between the return of college students to the city and Wednesday's deadline. Cuddyer expects more students to register between the preliminary and general election on November 5.

Almost 2,500 absentee ballots have been requested for the Sept. 24 preliminary election. Cuddyer credits the string of recent elections with causing "voter fatigue." Boston has held 12 different elections around the city this year alone, according to Cuddyer.

A registration surge prior to last year's presidential election also helps explain the lack of new registrations leading up to the City Hall elections.

City Councilor John Connolly's mayoral campaign is one of the few to submit registration forms so far, according to Cuddyer, who said other campaigns may be holding off or not labeling forms.

Connolly spokesperson Martha Bixby said the candidate has been meeting with small groups of people throughout the campaign and staff have followed up with those who may not be registered.

Lawrence DiCara, an attorney and former Boston City councilor who ran unsuccessfully for mayor in 1983, attributes Connolly's registration success to his early entry into the race, having declared his candidacy in March, long before most of his opponents.

In a statement to the News Service, Bridgit Brown, a spokesperson for former state representative and Patrick administration official Charlotte Golar Richie, wrote "Our campaign has been very active in voter contact, which includes voter registration."

Matthew Patton, a spokesperson for John Barros, said the campaign's "Stand Up Now" initiative of public registration drives has resulted in hundreds of new voters. "This initiative was all about engaging residents and making sure that they are part of the political process," he said.

"We're looking forward to a solid turnout across the board - from new voters and what we commonly refer to as the 'super voters' who never miss an election," S.J. Port, a spokeswoman for Rep. Martin Walsh's campaign said in an e-mail.

A spokesperson for Councilor Mike Ross' campaign said the campaign is identifying voters who may have signed up during the registration drives for President Barack Obama or the two U.S. Senate races for Sen. Elizabeth Warren and Edward Markey, but who haven't traditionally voted in municipal elections.

DiCara said this election cycle's new registration numbers may seem low since registration traditionally hits a high point right before presidential elections. The long ballot for mayor this year could also be causing some trouble for those looking to bolster the rolls.

"I think it's complicated things as much as anything else," DiCara said.