SANTIAGO (Reuters) -Workers at BHP's Escondida, the world's largest copper mine, rejected an offer for a new collective bargaining agreement, setting the stage for a potential strike, the union said on Thursday.

A total of 2,371 workers, or about 99.75% of union members, voted in favor of the strike. In a statement, the union said the call for a strike was "overwhelmingly backed by partners" that saw the offer made "no legitimate progress towards worker goals."

The union reiterated its demand for 1% of dividends to distribute equally among workers and said the current offer by the company also extended work days and cut benefits.

The statement said the current offer uses "one-time bonuses that try to hide the definitive loss of conditions."

Chilean legislation lets either party call for five days of government mediation, extendable by another five days if both parties agree, to avert a strike.

In a statement, BHP said it would request government mediation in "the coming days" and hopes to reach "an agreement compatible with worker aspirations and Escondida's future sustainability."

BHP owns more than half of Escondida, along with Rio Tinto and JECO Corp.