Former state Rep. Gil Riviere, who represented the North Shore in the House for one term before losing in the Republican primary last year, said he will switch political parties and become a Democrat as he tries to reclaim the seat next year.

Riviere, a mortgage broker who lives in Waialua and is active with the conservation group Keep the North Shore Country, said he has greater rapport with Demo­crats on environmental and conservation issues and would be more effective in the state’s dominant political party.

"I think I can be a really good, strong voice for that part of the Democrat platform," said Riviere, who plans to sign his party card on Friday.

Riviere, who was elected in 2010, lost to Rep. Richard Fale (R, Waialua-Kahuku-Wai­ahole) in the Republican primary last year by 76 votes. Riviere’s district had been reconfigured after reapportionment into a new House District 47 that covers much of the North Shore and part of Windward Oahu.

Riviere held the Haleiwa and Sunset Beach side of the district in the primary, while Fale, who had run unsuccessfully before on the Windward side, won in Kahuku and Hauula.

The dilemma for Republican candidates in Hawaii who appeal to voters from both parties is that usually only a fraction of the most committed Republican voters pull GOP ballots in primaries. Last year, just 17 percent of voters statewide pulled Republican ballots in the primary, 32 percent in House District 47.

Fale, a Mormon, was lifted in the general election last year by the surge of support in Mormon-dominated Laie for former Massachusetts Gov. Mitt Romney, a Mormon who was the Republican presidential nominee.

Riviere, a moderate, and Fale, a conservative, differ most on development issues. Riviere has fought the expansion of Turtle Bay Resort and the Envision Laie project, while Fale is open to development that will help with job creation, particularly for residents in communities such as Hauula, which struggles with poverty.

"If we put a brick in the ground, and it helps the people in my community, and it helps bring those kids out of poverty, I’m for the brick," Fale said. "If I put the brick in the ground, and it doesn’t help my kids, doesn’t help my families, doesn’t help our senior citizens, doesn’t help bring those kids out of poverty, then I’m against the brick."

David Chang, the state GOP chairman, described Riviere’s decision as personal rather than a reflection of Republican weakness. Riviere had appeared at the Oahu Republican convention in March and had led a candidate training class.

"It’s more of a personal grudge and a personality conflict that’s taking precedence," Chang said. "And I think that it doesn’t do his North Shore or his district any favors."

Riviere said he made his decision after the Oahu Republican convention.

"At that time, I was still willing to do my part for the party," he said. "But my decision came somewhere between then and now."

A stream of Republicans have switched parties over the years in a state that Democrats have dominated politically since the 1950s. The last two politicians to switch were Rep. Karen Awana (D, Kalaleloa-Ko Olina-Maili) and Sen. Mike Gabbard (D, Kapolei-Makakilo) in 2007.

Former Gov. Linda Lingle, speaking at the state GOP’s annual Lincoln Day dinner in April, skewered Republican politicians who have changed parties.

"These party-switchers are an adult political version of high school students abandoning lifelong friends because they want to hang out with the cool kids," she said. "They want to fit in. They want to be popular. And besides, it’s easier to be a Democrat in Hawaii. You might get to chair a committee. And lobbyists and special-interest groups care more about your position on pending legislation."

Riviere’s switch comes as Democrats are again going through their own internal turbulence over political candidates who lack fidelity to the party’s platform. The party is preparing a lawsuit to close primaries so that only voters who declare their affiliation with the party can participate.

Democrats worry that allowing all voters to participate in the party’s primaries dilutes the nominating process and produces candidates who are not always faithful to the party’s agenda.

Dante Carpenter, the chairman of the Democratic Party of Hawaii, said the party continues to welcome former Republican candidates like Riviere.

"I think that we will have to make sure they’re not doing it for convenience," he said.