"The manufacturing industry is running out of low-cost sourcing destinations, and it's time to invest in making factories safer and better, rather than searching for cheaper labor, " says Auret van Heerden, chief executive of the Fair Labor Association, a monitoring group funded partly by Western companies.

WSJ: Apparel Retailers Confront Tough Options

Apple also said it is joining the Fair Labor Association, agreeing to outside monitoring of its suppliers.

WSJ: Apple Details Working Conditions at Factories

Scott Nova, executive director of the Worker Rights Consortium, a Washington-based nonprofit monitoring group, said labor-rights groups' calls for better safety measures at Bangladesh factories had been met with "vague promises" from retailers.

WSJ: At Least 200 Die in Bangladesh Building Collapse

Chung Yong-Jin announced his resignation as vice-chairman of the board of retail giant Shinsegae Group in late February 2013, following investigations by the labor ministry into charges that the group was illegally monitoring employees to prevent them from joining a union.

FORBES: Chung Yong-Jin

The company has a code of conduct for its manufacturing partners prohibiting child labor, forced labor, or hazardous working conditions, and checks for compliance via regular third-party monitoring, he said.

WSJ: 3 Die in Cambodia Factory Collapse