In the latest wrinkle of an ongoing labor dispute, the teachers union plans to file an ethics complaint against the state, alleging the governor tried to influence the Hawaii Labor Relations Board.

The union pointed to an Aug. 10 letter from the governor, superintendent of schools and chairman of the Board of Education in which they called on the board to hold a settlement conference to designate a mediator and set parameters for future negotiations.

Hawaii State Teachers Association President Wil Okabe said Sunday the letter violates state labor laws and "taints the HLRB process in a manner that will leave open to question the inherent ability of the board to make decisions based on public hearings."

Okabe said HSTA’s executive board voted Saturday to file its complaint with the state Ethics Commission, after trying to persuade the governor to formally withdraw his Aug. 10 letter.

The ethics filing comes more than a month after the state unilaterally implemented its "last, best and final" contract offer for teachers, citing an impasse in negotiations and an urgent need to realize labor savings. The offer for Hawaii’s 12,500 teachers included wage reductions and higher medical premiums.

The state says the "last, best" contract offer, which went into effect July 1, was needed to avoid layoffs. The union, meanwhile, says the state violated members’ rights when it imposed a contract offer, an unprecedented move in Hawaii public-sector negotiations.

Both parties will be before the HLRB today for the start of proceedings in the union’s "prohibited practice" case against the state. Hearings are scheduled to run through Wednesday.