The state Office of Elections needs an additional 300 volunteer poll workers on Oahu for Saturday’s primary election even as nearly 68,000 people already have voted on Oahu through absentee ballot or early walk-in voting.

The shortage of volunteers on Oahu is slightly greater than normal this close to an election, said Rex Quidilla, spokes­man for the state Office of Elections.

"We normally have a little more (volunteers), but we’re getting people dropping out at the last minute," Quidilla said. "It’s two steps forward, three steps back."

The Office of Elections will hold its final orientation session for volunteer poll workers at 6:30 tonight at the Aiea High School cafeteria for anyone who still wants to volunteer to work Saturday, Quidilla said.

In all, elections officials will rely on 3,100 volunteers across the islands to help staff 233 voting sites on Saturday, including 142 on Oahu.

People who are still unsure where they need to vote Saturday can find their polling site by using the Office of Elections online polling place locator at elections2.hawaii.gov/ppl.

For the primary election, 687,500 voters have registered statewide, with 461,896 of them on Oahu.

As of Monday the Hono­lulu City Clerk’s office had mailed more than 102,350 absentee ballots; 60,578 had been returned.

Another 7,409 people voted early at walk-in absentee voting sites at Hono­lulu Hale, Kapolei Hale and the Pali Golf Course banquet hall.

Walk-in voting ends Thursday on all islands.

Hawaii is approaching the day when a majority of voters will cast their ballots before the polls open on election day — either via walk-in early voting sites or by mail-in absentee ballot.

In the 2000 primary election, 18 percent of voters on Oahu and 20 percent statewide voted early. In the 2006 primary those figures had grown to 36 and 34 percent, respectively. By 2010, 45 percent of Oahu voters and 44 percent statewide voted early in the primary in the first three days.

This year the first three days of early primary voting, which began July 30, showed a slight increase compared with the 2010 primary.

About 2,701 Oahu voters walked in early or mailed in their ballots in the 2010 primary election.

This year 3,113 voters mailed in their ballots or walked in to vote in the first three days, City Clerk Bernice Mau said.

"You see the numbers rising," she said. "We’re looking at it increasing again this year."