JUNEAU — The group opposing a ballot measure that would re-establish a coastal management program in Alaska raised more than $683,800 in three weeks, a majority of that from big oil companies, and held a huge cash advantage heading into next week’s primary.

In all, “Vote No on 2” has raised about $1.5 million in what’s become the most expensive race in Alaska so far this year and had more than $393,100 on hand as of Aug. 18. The Alaska Sea Party, the group behind Ballot Measure 2, has reported raising a total of more than $204,700, including about $54,600 between July 28 and Aug. 20.

The bulk of the funding for Vote No on 2 has come from resource development and industry groups, though campaign manager Willis Lyford said in a statement that labor unions, local chambers of commerce and others have also voiced opposition to the initiative.

During the recent reporting period, from July 28 to Aug. 18, Vote No on 2 reported raising about $683,800, with the major three oil producers in Alaska — BP Exploration Alaska, ConocoPhillips Alaska and Exxon Mobil Corp. — accounting for about $401,000 of that, in direct and nonmonetary contributions. Pebble Limited Partnership and Sumitomo Metal Mining Pogo LLC, two mining groups, each contributed $75,000.

“Our fundraising results reflect the deep concern with Ballot Measure 2 among a broad cross section of businesses and industries,” Lyford said. “Ballot Measure 2 is bad for jobs and bad for Alaska’s economy, and those donating to us recognize that.”

Bruce Botelho, chairman of the Alaska Sea Party, said the opposition’s fundraising “is really being driven by corporate interests,” acting not on behalf of Alaskans but based upon their shareholder interests. The biggest check cut to the Alaska Sea Party during the recent reporting period was $25,000 from Robert Gillam, founder of an Anchorage-based investment firm who also has made a name fighting the proposed Pebble Mine.

There are no limits to what an individual, business, union or group can give to a ballot group in Alaska.

Botelho said his group went up with its first radio ads on Monday and plans a TV spot heading into Tuesday’s election. Vote No on 2 began running its first ads weeks ago.

Alaska had a coastal management program for decades, but it ended last year, after the Legislature and governor failed to come to terms on its reauthorization. Ballot Measure 2 will appear on Tuesday’s ballot.

Opponents of the measure said they’re not against Alaska having a coastal management program but have a problem with the type of program laid out by the initiative. Among other things, they said it would create confusion and could hinder development. Supporters said the proposal would give the state a meaningful say on federal decisions affecting Alaska’s coastal areas, help coordinate the permitting process and cut through red tape.