SEOUL (Reuters) - Hyundai Motor's <005380.KS> unionized workers in South Korea overwhelmingly voted down a tentative wage deal agreed with the automaker, signaling more strikes and production losses at its biggest manufacturing base.

A total of 78 percent of 45,777 union voters turned down the agreement, while 22 percent approved the deal, a union spokesman said on Saturday.

On Wednesday, Hyundai Motor and its labor union in South Korea reached the preliminary deal, which is less generous than last year's package.

Workers at Hyundai Motor's plants in South Korea staged sporadic walkouts between July and August over annual wage demands, leading to a production loss of 65,500 vehicles worth 1.47 trillion won ($1.3 billion).

Hyundai Motor, the world's fifth-biggest automaker together with affiliate Kia Motors <000270.KS>, has been hit by strikes in all but four of the union's 29-year history although it usually makes up for lost output by the end of each year.

(Reporting by Hyunjoo Jin, editing by David Evans)