A new three-year contract that covers roughly 1,300 unionized Hawaiian Electric Co. workers provides wage increases of up to 3 percent in each of the years, but the pact requires that employees increase their contributions to benefits, according to a federal regulatory filing.

The members of the International Brotherhood of Electrical Workers Local 1260 went on a one-week strike March 4-11 after rejecting a tentative contract agreement reached between HECO management and union leaders on Feb. 18. HECO union members ratified the new contract last week.

Neither the IBEW nor the company would comment on the details of the new agreement, but HECO’s parent company disclosed information about the contract in a filing this week with the Securities and Exchange Commission. Because Hawaiian Electric Industries Inc. is publicly traded, it is required to disclose such information under federal securities law.

The agreement calls for noncompounded wage increases of 1.75 percent in 2011, 2.5 percent in 2012 and 3 percent in 2013, according to the filing. That follows noncompounded wage increases of 3.5 percent in 2008, 4 percent in 2009 and 4.5 percent in 2010.

The new contract also makes changes to workers’ medical coverage and retirement benefits, but the SEC filing was unclear about which employees would be affected.

"The new benefit agreement covers a term from January 1, 2011 to October 31, 2014 and includes changes to medical, dental and vision plans and increased employee contributions and changes to retirement benefits for employees commencing employment on or after May 1, 2011," HEI said in the filing.

Contract negotiations had been going on since September. The contract was extended for three more months when no deal had been reached by the original expiration date of Oct. 31.

Negotiators reached a tentative agreement on Jan. 31, the last day of the extension. However, union members rejected that agreement on Feb. 18, setting the stage for the eventual walkout on March 4.

Contract talks are scheduled to begin in August between IBEW Local 1357 and Hawaiian Telcom. That contract expires Sept. 12.