A clear leader has emerged in the fundraising race for the governor’s office.

Former Honolulu Mayor Mufi Hannemann raised more money than his rivals in the first half of 2010. He has more than four times as much money on hand as his Sept. 18 primary opponent, former congressman Neil Abercrombie. And he more than doubled the collections of Republican Lt. Governor James “Duke” Aiona, who has barely more than a third as much cash on hand as Hannemann.

Hannemann and Abercrombie face off in the Sept. 18 Democratic primary. The winner is expected to face Aiona in the Nov. 2 general election.

The financial results became public Monday as the candidates filed their first financial reports this year. This first preliminary primary report, as it’s called, offers an account of all money raised and spent from Jan. 1 to June 30. Abercrombie hadn’t filed a report with the state by 6:30 p.m. Monday, but did issue a press release in the late afternoon outlining his record.

Here are the details:

James “Duke” Aiona

Aiona’s total contributions from Jan. 1 to June 30 came to $370,792. He also took in $3,338 in bank interest, refunds and reimbursements, bringing his total receipts for the reporting period to $374,130. His total receipts for the entire election cycle come to $2,406,178.

Aiona spent $521,235 in the first half of this year and $1,883,350 through the whole election cycle. As of June 30, he had $718,892 on hand.

The biggest recipient of Aiona’s spending was Meridian Pacific, Inc, a California-based company that specializes in campaign management, media production, and direct mail, among other areas. In 18 transactions, the campaign paid Meridian Pacific $148,717. According to the company’s website, Meridian has “developed, implemented and managed dozens of candidate and ballot measure campaigns utilizing radio, television and direct mail.” The report shows that most of the campaign’s payments to Meridian related to a variety of services, including consulting, printing, postage, T-shirts, rally signs and business cards, to name a few.

The Aiona campaign’s biggest single transaction was with The Tarrance Group Inc., a national Republican polling firm based in Virginia. In June, the company received $31,039 for surveying voter attitudes in Hawaii.

Read Aiona’s disclosure report.

Mufi Hannemann

Hannemann’s total contributions from Jan. 1 to June 30 came to $822,305. The campaign also received $3,218 in refunds and bank interest and a loan of $2,117, adding up to total receipts of $827,641. Over the election period to June 30, Hannemann’s total receipts amounted to $2,486,158.

Hannemann spent $852,400 during the first half of the year and $1,152,838 over the whole election cycle. He had $2,005,399 on hand, as of June 30. (Hannemann had $672,079 cash on hand when the governor election period began, which means he’s had $3,158,237 to use for the race.)

A press release from the Hannemann campaign noted that contributions from controversial Pittsburgh donors have been returned, though they are still counted as contributions because “they were not sent back to donors within 7 days of receipt.” He hadn’t properly notified the campaign spending commission about a Pittsburgh fundraiser held while he was on a trip to Washington, D.C., to meet on Honolulu’s rail project, and promised to return any donations he received at the event.

Read Hannemann’s disclosure report.

Neil Abercrombie

Abercrombie brought in total contributions of $711,655 during the first half of the year, lifting his total receipts over the election to $2,058,612. He had no loans or other receipts this period.

The campaign spent $1,129,518 over the reporting period and $1,589,669 in the whole election. He has $468,942 on hand, but unpaid expenditures and debts of $127,175, leaving him with a surplus of $341,767.

Read Abercrombie’s disclosure report.

DISCUSSION: Refresh this page to read more campaign finance updates Tuesday. In the meantime, talk about the Hawaii governor’s race in our discussion.