Foxconn, a main supplier for Apple's iPhone, says it has stopped interns from working illegal overtime at its factory in China.
The announcement comes after a Financial Times report found at least six students worked 11-hour days at its iPhone X plant in Henan province. The practice breached Chinese laws preventing children from working more than 40 hours per week.
About 3,000 students were reportedly hired to work at the Zhengzhou plant.
Apple said the secondary school students worked voluntarily but they "should not have been allowed to work overtime". Both the tech giant and Foxconn have said the interns were "compensated and provided benefits".
"Apple is dedicated to ensuring everyone in our supply chain is treated with the dignity and respect they deserve," the firm said in a statement. "We know our work is never done and we'll continue to do all we can to make a positive impact and protect workers in our supply chain."
The Foxconn Technology Group, which operates an internship program at the Chinese factory, told the BBC in a statement that it took "immediate action to ensure that no interns are carrying out any overtime work".
It added that "interns represent a very small percentage" of its workforce in China and that the breach of labor laws was inconsistent with its own policies.
The Taiwanese firm reportedly hired the students in September to keep up with demand for the new iPhone X, which Apple has described as being "off the charts".