US human rights and trade union groups are launching a campaign aimed at restricting US imports of goods made under alleged sweatshop conditions.

Many US companies say they abide by voluntary codes of conduct to improve working conditions in overseas factories.

But campaigners say the conduct codes are not always implemented.

They now want to pressure Washington into introducing new laws that could punish firms if they fail to uphold their own declared standards.

Law needs updating

One of the focuses of the campaign is Bangladesh where the garment industry is the largest employer - but one which has virtually no regulation.

The Bangladesh Garment Manufacturers & Exporters Association (BGMEA) is now working on their own code of conduct to protect workers.

Sheng Jie Li from the International Labour Organisation told the BBC's World Business Report that the current legislation was too old.

"The Factories Act was last amended in 1965," he said.

And some of its legal requirements do not apply to the garments industry.

"Under this project we would like to set up an industry-wide code of conduct," he said.

"We hope this code of conduct will provide protection for workers."