Nic Bothma / EPA

Striking workers blocked a road and set a bulldozer ablaze in South Africa.

DE DOORNS, South Africa -- Police fired rubber bullets and stun grenades Wednesday at hundreds of striking farm workers who blocked a highway in the grape-growing Western Cape, heart of South Africa's multibillion-dollar wine region.

The strikers had piled burning tires across the main highway through the town of De Doorns, 60 miles east of Cape Town, to demand higher wages, a Reuters reporter on the scene said.

Four people were hospitalized for minor injuries from rubber bullets as police dispersed the crowd, an emergency worker said.

"I can confirm that 41 people have been arrested, but that number could rise," said police spokesman Andre Traut.

The strikers set bushes, a bulldozer and a trailer on fire, sending smoke billowing into the sky.

After the crowd had scattered, police removed large rocks that protesters had used to block the road. Empty rubber bullet cartridges littered the ground near the highway.

PhotoBlog: Violent labor strikes expand to South African farms

Africa's largest economy saw waves of labor unrest last year that began in the platinum mining industry and swept through the trucking and agriculture sectors.

The strike by farm workers in the Western Cape follows a similar walk-out in December in which warehouses were set on fire and at least two workers died in clashes with police.

'No food on the table'

The workers, many of them black seasonal hires employed to pick and pack fruit on farms owned mainly by the white minority, want a minimum daily wage of 150 rand, or $17.44, up from 69 rand.

"We are struggling. It is very difficult to survive on 69 rand a day. School is starting and we don't have money for school clothes," said Lena Lottering, 35, a mother of three. "There is no food on the table and my children often go to bed hungry."

Another worker, Aubrey Louw, 47, said he had worked on the farms since the 1970s, when he received 45 rand a day.

"Now we get 65 rand. What is that? We want 150 rand. Farmers would rather employ security guards and buy new cars than pay us," he said.

When talks to avert the strike broke down this week, union leaders blamed the intransigence of the white farmers, highlighting the racial and financial divisions that continue to rankle 18 years after the end of apartheid.

"We have been met with naked racism and white arrogance," said union leader Nosey Pieterse, general secretary of the Bawsi Agricultural Workers Union of South Africa.

More world stories from NBC News:

• 150 years old and still running late: London Tube reaches landmark
• Family escapes 'tornadoes of fire' by clinging to jetty for 3 hours
• Video: How happy is the only country to track happiness?
• Flag debate sparks rioting in Northern Ireland
• World's best frenemies: Karzai, Obama set for key talks
• Video: Death art encourages living to seize the day
• 10ft squid captured on film in natural habitat
• Experts: 'Horrible' sea level rise plausible by 2100

Follow World News from NBCNews.com on Twitter and Facebook