About 47,000 workers at Hyundai Motor Co. are striking to protest the automaker's decision to spend $10 billion on land for a new headquarters.

Union spokesman Hwang Ki-tae said Thursday the mood among workers turned sour after a Hyundai-led consortium offered 10.55 trillion won ($10.1 billion) for land in Seoul's upmarket Gangnam district. They are walking off the job for a total of 12 hours this week.

Since June, the union has been in talks to negotiate new terms for wages and benefits. The latest talks broke down after the company refused to accept the union's proposal, citing costs.

Hwang said the land deal showed that Hyundai's position could not be justified. Hyundai is paying about three times the land's value to squeeze out other bidders.

Hyundai has 60,000 workers.