Thousands of protesting workers in Bangladesh set fire to at least six garment factories after at least one of their colleague was killed and scores were injured in clashes with police, witnesses and police said on Tuesday.

Bangladeshi textile workers during a demonstration. Several people were injured when security forces fired live rounds to disperse tens of thousands of textile workers protesting for higher wages near the Bangladesh capital.[AFP]

They said more than 100 vehicles were damaged in the violence that first erupted on Monday in and around capital Dhaka after police called in by factory owners tried to break demonstrations by workers demanding higher pay and benefits.

Agitated workers set fire on Monday to three factories in an export zone in Savar, about 25 km (15 miles) north of Dhaka. Later, they barricaded a highway and attacked buses and trucks.

The violence spread to other areas overnight when thousands of workers armed with sticks and stones attacked factories in the city's Uttara, Mirpur and Tejgaon areas and its suburbs.

"The violence is still spreading and it might be worsen," a police officer said.

Fire engines could be seen racing through Dhaka's crowded streets on Tuesday.

"We are battling fire in at least half a dozen spots right now," a fire fighter said by telephone.

Authorities had called in riot police to try and bring the situation under control, officials said, after about 100 people, including police, were injured in the clashes.

Garments are impoverished Bangladesh's biggest export, fetching the country more than $6 billion a year. The industry employs nearly 2 million workers.

Bangladesh Garment Manufacturers and Exporters Association expressed concern over the worsening law and order.

"This is part of a conspiracy to ruin the nation's economy," it said in a statement.

Bangladesh is already reeling under widespread civil unrest over nagging shortages of electricity and drinking water for months.