NIAGARA FALLS — A human error on election night may have resulted in hundreds of votes initially going unreported in the race for New York’s 60th Senate seat, a spokesman for Republican district challenger Mark Grisanti said late Thursday.

Grisanti spokesman Doug Curella said unreported votes from one or more voting machines in Erie County were discovered during a scheduled audit Thursday — and when counted, increase Grisanti’s lead to 812 votes over incumbent Antoine Thompson, D-Buffalo.

“After checking the tapes in the machines the new total includes an extra 135 votes (for Grisanti) ...” Curella said of the numbers he said weren’t reported to county elections officials when initial unofficial returns were being tracked Nov. 2.

Affidavit and absentee ballots are still being counted in both Erie and Niagara counties and tallies are nearly complete, with Grisanti’s lead having increased to 677 votes Thursday before the missing votes were discovered, boosting Grisanti’s lead to the revised 812, on a day the campaign was already celebrating an apparent swing among absentee voters.

On Tuesday, Senate Democratic Committee spokesman Travis Proulx said 2,711 absentee ballots were issued and that 65 percent of them were issued to voters likely to re-elect the incumbent. But no such comeback has yet materialized and the numbers continue to favor Grisanti, a registered Democrat who switched to run against Thompson on the GOP ticket.

Affidavit ballots in Erie County remain to be counted. There are still 1,800 uncounted affidavit ballots in that county, which should be tallied by Monday, Curella said.

State Sen. George Maziarz, R-Newfane, said he’s confident Grisanti will win the election and predicted Democrats’ call for a hand count of each and every vote likely won’t be approved, citing calls by Gov.-elect Andrew Cuomo and the state’s chief judge that outstanding elections be resolved quickly.

“With an 812 vote lead this is going to be wrapped up by Thanksgiving,” Maziarz said. “It becomes a mathematical impossibility for them to take the lead ...”

Should the Thompson camp continue its legal challenge, New York Chief Judge Jonathan Lippman has set forth a series of deadlines for court dates in the state’s three remaining unresolved races. Lippman, acting on Cuomo’s request, wrote an administrative order that requires trial court rulings by Dec. 6, midlevel court reviews by Dec. 15 and hearings at the top Court of Appeals by Dec. 20.

Cuomo has said he would like to have a working majority in the state Senate by Jan. 5. The Senate currently is split 30-29 in favor of Republicans and if the three recounts drag on, neither party would have a majority 32 votes needed to pass a bill.

A number of the ballots in the 60th district race have been contested for a range of reasons by lawyers on both sides and military ballots may be received until roughly Thanksgiving, meaning they will still factor into the final totals.

Democrats have called for a hand count of each and every vote cast. Proulx previously said the request was made shortly after the election, and was again urged after a voting machine software glitch on Monday caused some machines in Erie County not to provide totals.

State board of elections  workers were in town late Thursday looking at machines regarding the alleged glitch, which had caused error messages during a customary canvassing of a small percentage of machines Monday.

Proulx could not be reached Thursday to comment on where the request for a hand-count — which must be approved in state court — stands.

“I can’t see any way that they will allow a hand recount,” Maziarz said. “An audit of the machine has proven (them) to be 100 percent correct. What happened is the two machines were not reported on election night, there was no mechanical problem whatsoever.”

Curella said Grisanti’s increasing lead is encouraging to his camp, and may gain even more ground once the contested absentee ballots are ruled on, perhaps as early as today.

“We’re optimistic that that number could increase once these objections are ruled on,” he said.

Maziarz, who was present during counts Thursday, said one of Thompson’s’ head lawyers, Michael Gianaris, left to go back to New York City today, which he took to mean Thompson’s campaign is throwing in the towel.

“He knows it’s over,” Maziarz said.

The Associated Press contributed to this report.