DHAKA: Workers at a Bangladeshi garment factory on Monday freed a garment factory boss they had held captive in his office for more than 18 hours after he paid a promised bonus.

The incident was the first involving the forced confinement of a factory boss in months of confrontation between management and workers earning minimum wages equivalent to $38 a month, half what Cambodian garment workers earn.

A trade union leader said the incident was a “positive development” as workers had achieved their aim “peacefully”.

Police said workers went to the Tuba Group factory on Saturday to demand payment of their bonus for the Eidul Azha holiday.

They forced their way into the office of owner Delwar Hossain and locked him in when he said no money was available.

Police, relatives of the owners and the factory owners' group, the BGMEA, launched talks with the protesters and a police official said Hossain was released after bonuses were paid to 900 workers late on Sunday.

“I see it as a positive movement as the workers were not violent and were able to realise their demand peacefully,” said Amirul Haque Amin, president of the National Garment Workers' Federation trade union.

An official of the BGMEA said bonuses totaling 5 million taka ($64,000) were paid.

Each worker was to receive a month's wages, which can range up to the equivalent of $155 for an experienced employee.

S M Mannan, a BGMEA vice-president, said his group had issued instructions to pay bonuses. “If any owner does blunder, we cannot take responsibility for him,” he told Reuters.

Workers have at times staged violent protests to seek an increase in the minimum wage to $100, with demonstrations shutting down more than 600 factories last month.

A series of accidents, including a building collapse in April that killed more than 1,100 people, has raised global concern over standards in Bangladesh's $22 billion garment industry.

Garments are a vital sector for Bangladesh and its low wages and duty-free access to Western markets have helped make it the world's second-largest apparel exporter after China.

The recent accidents have put the government, industrialists and the global brands that use the factories under pressure to reform an industry that employs four million and generates 80 per cent of Bangladesh's export earnings.