Apple said in a report that it found nearly one third of its suppliers, which sprawls throughout Asia, failed to abide by Apple’s standards on wages and benefits, and five facilities employed underage workers, the Wall Street Journal said.

Apple listed 156 suppliers in its recent 27-page report that details working conditions throughout its supply chain, including both world’s technologic giants such as Sony Corp and Intel Corp, as well as small names like Tianjin Lishen Battery Joint-Stock Co. Ltd. in China.

The report makes several references to one of Appple’s biggest manufacturing partners, Hon Tai Precision Industry Co, also known as Foxcoon. The company was grappled with a spate of employee suicides at a facility in Shenzhen, China in 2010, and an explosion that killed four workers and injured 18 at a plant in Chenngdu, China last year.

The company has established new requirements for firms dealing with combustible dust after the blust in Chengdu and an explosion at another supplier’s factory in Shanghai, which injured 59.

Apple has been facing pressures from activists both from the western countries and Asia. They have continuously filed complaints over the poor working conditions in many of its supplier’s factories, especially those in China.

Apple’s report may have ruffled Beijing that has long been seeking ways to block criticism and disclosure of domestic business activities.

The huge Chinese market has been growing more and more important for Apple. Last Autumn, the firm reported the quickest growth in the region with annual sales at about 13 billion U.S. dollars.

Demands for Apple’s iPhone, iPad and Mac have soared last year and the retailing stores in Beijing and Shanghai have some 40,000 visitors every day.

At the same time, Apple said it was still dealing with the impact from the halt of sales of iPhone 4S last Friday in Beijing on its first debut in the mainland after crazy buyers pelted eggs and smashed windows outside the Apple stores.