The Hawaii State Teachers Association, representing more than 12,000 public school teachers, has ended mediation with the state in its continuing contract dispute, Gov. Neil Abercrombie announced Thursday night.

"The federal mediator has informed us that HSTA is ending their participation in mediation," Abercrombie said in a news release. "I am very disappointed that HSTA once again is not willing to engage in discussions that could resolve outstanding issues."

Union President Wil Okabe said the teachers went to mediation with genuine sincerity and an awareness that the teachers’ contract will affect the future of public education in Hawaii.

"In the coming weeks, HSTA will provide our teachers and the public a more detailed accounting of what led up to the breakdown in bargaining with this governor," Okabe said Thursday.

He said Abercrombie violated ground rules of mediation by issuing a statement to the news media by himself and not jointly with the union.

The teachers union agreed with the state Aug. 20 to seek the help of the Federal Mediation and Conciliation Service.

Abercrombie said his administration remains willing to engage in mediation.

"It is impossible to negotiate with people who refuse to talk," Abercrombie said.

The labor dispute began in July 2011 when the state unilaterally implemented a "last, best and final" contract offer for teachers that included wage reductions and higher health insurance premiums.

The teachers union filed a complaint with the Hawaii Labor Relations Board on July 8, alleging the state violated the collective bargaining process and did not bargain in good faith.

The complaint seeks to nullify the state’s "take-it-or-leave it" bargaining.

The union announced Sept. 28 that it filed a petition with the state Supreme Court to order the Hawaii Labor Relations Board to issue a decision on its complaint against the state.

The union has argued that the state’s imposition of a contract violated its members’ rights and collective bargaining laws.

The state said it had to act to avoid massive layoffs.

In recent months the state has repeatedly asked teachers to return to bargaining while the union believes a six-year agreement teachers had previously rejected, then approved in May, should be honored.

Abercrombie said the agreement is invalid and that a new deal needs to be negotiated.

The lack of movement on the issues means teachers continue to work under the "last, best" offer, which expires June 30.

Under the agreement union members approved in May, teachers would continue to take 5 percent wage reductions through June 30 before moving to a new salary schedule that recognizes teachers’ years of service.

The state Department of Education would also move to a revised teacher evaluation system linked to student performance. Teachers rated "effective" or higher would be eligible for annual raises.