Updated

Alaska voters have retained a new petroleum production tax system that offers hope of increased investment and jobs but drew criticism as a giveaway to already profitable oil companies.

The state Division of Elections counted 17,721 absentee and early votes Tuesday, giving repeal opponents the victory. The "no" side increased its lead from 6,880 to 8,443 votes. The unofficial overall count was 90,150 to 81,707, giving the no side a 52.5 percent edge.

"The results confirm that voters decided to give the oil tax structure a chance to work," said Willis Lyford, spokesman for the Vote No on 1 campaign.

Gov. Sean Parnell's "More Alaska Production Act" took effect Jan. 1.

It replaced the system championed by former Gov. Sarah Palin, "Alaska's Clear and Equitable Share," or ACES, which gave tax credits for investment but contained a progressive surcharge that took a larger tax bite from company profits when oil prices increased.

Oil companies lobbied for changes. They said ACES made investment planning uncertain and investment elsewhere more likely.

ACES supporters acknowledged flaws in the Palin law but said it should be tweaked, not tossed. They called the Parnell plan a giveaway to oil companies with no provision to guarantee new investment.

The vote no campaign had the more difficult message, Lyford said. Repeal opponents, he said, gave voters a simple message: Don't trust the oil companies, they make billions already.

"We had to say, `It's more complicated than that,"' he said.

The campaign was all about fixing the problem of declining oil production, which has seen output in the trans-Alaska pipeline fall from a high of 2 million barrels per day in 1988 to 547,866 barrels in 2012, Lyford said.

The decline has already flattened out, he said. Petroleum companies also linked a tax revision to a liquid natural gas project, he said.

"That's a massive new investment opportunity for the future," Lyford said.

Alaskans voted Aug. 19 on the tax measure, appearing on the ballot as Ballot Measure No. 1. The margin was too narrow to call immediately after the election when at least 33,700 votes remained to be counted.

Voters cast 171,857 votes Tuesday on the 2013 petroleum tax system.