Garment factories in Bangladesh have sacked hundreds of workers since protests demanding higher wages erupted in October, three labor unions representing half a million workers told Reuters this week, while many others have fled fearing arrest.

Clashes during the protests, which ran alongside wider anti-government demonstrations by the opposition ahead of the Jan. 7 general election, killed four workers and injured dozens of others, with the police filing cases against hundreds of unidentified people for vandalism.

The government agreed in November to raise minimum wages by more than 56% to 12,500 taka ($114) a month, which many workers have still called too low. Bangladesh has become the world's second-biggest garment exporter after China partly thanks to low wages.

The three unions – Bangladesh Garments and Industrial Workers Federation, National Garment Workers Federation and Bangladesh Garments Workers Unity Council – estimated that 1,000 to 5,000 workers had either been fired in the last two months or had gone into hiding.

But Faruque Hassan, president of the Bangladesh Garment Manufacturers and Exporters Association, said he was not aware of any retrenchments, adding that the industry body would act if "any such incidents are brought to our notice".

Bangladesh's Ministry of Labor did not respond to a request for comment. Momanul Islam, a senior police official in Ashila, a garment hub, said police had not arrested any garment workers for joining the protests.

Bangladesh's more than 4,000 garment factories rely on some 4 million workers to supply major Western brands.

In October, brands including Abercrombie & Fitch, Adidas, GAP, Levi Strauss, Puma and PVH and Under Armour urged the government to ensure there was no retaliation against workers seeking fair wages.

Delowar Hossin, a garment worker with Ducati Apparels, said he was fired earlier this month without any explanation or payment of severance dues.

"I was just blocked from entering the factory," said Hossin, who now works part-time as a mason.

Ducati's managing director, Khayer Mia, said some 15 to 20 workers had vandalized the factory during the protests but said that no workers had been sacked. He said Ducati paid full salaries to all workers, even though the protests had shut the factory for 10 days.

"I love my workers and factory like my family," he said.