Workers at a car factory blocked the main highway from Bangkok to the seaside resort of Pattaya Wednesday after rejecting a year-end bonus, reported dpa.
Several high-profile labour disputes have broken out in recent weeks as the economy slows down and employers try to cut jobs and pay.
Two companies of police commandos were deployed when 300 workers of a plant producing cars for Ford Motor Co and Mazda Motor Corp at Rayong province south-east of Bangkok blocked the road after the company trimmed the workers' pay demands.
The Thai economy is expected to slow so that it barely grows next year as exports fall and the global economy weakens.
The recent week-long closure of Bangkok's major airports by anti-government protestors has also hurt not only high-value exports but an already thinner tourist industry.
Prominent Thai economist Ammar Siamwalla recently said a million Thais could lose their jobs next year if there was no sharp pickup in the world economy. The Commerce Ministry said earlier this week exports fell by 18.6 per cent in November, the first monthly drop in exports for six years.
Subcontract workers for the Thai Summit Auto Body Industry Co blocked the Bangna-Trat highway earlier this month, demanding higher year-end bonuses. The 400 workers demanded the same bonuses as full-time employees and a guarantee of no lay-offs in the near future.
Thailand's vehicle factories are reputedly globally competitive which enables their workers to exert pressure on the owners. Many of Thailand's other manufacturers and service industries are more fragile - laying off workers without causing much of a stir.