A China-based supplier for both Samsung and Lenovo has denied hiring underage labourers after a New York-based human rights organisation accused them of employing children.
Samsung said its investigation into the Samsung production line at the Huizhou factory of its supplier HEG Technology found no children or students were being employed.
A spokesman for Lenovo confirmed that the company would investigate the report.
China Labor Watch had reported that it found more than 10 children working at the HEG factory in an investigation over July and August. In addition, the NGO said its probe revealed more than 100 student workers who were not paid for overtime work or a night shift subsidy.
The human rights watchdog said it had shared the evidence of its investigation with Samsung in August and the company had insisted that the supplier pay some students working at the factory.
Reuters news agency reported that an employee at HEG Technology said the company had never hired children and that its facial recognition technology helped to ensure that its staff were not minors.
It said the minimum age of staff working on Samsung products was 18, while the youngest workers employed on the Lenovo production line were 16.
Samsung said in a statement that it had proposed a joint investigation with China Labor Watch to obtain "more precise verification" of the watchdog's allegations, adding that it had handed over the results of its investigation to the organisation.
"We find it regrettable that CLW issued the allegations today without any mention of our statement," Samsung said in a statement.
China Labor Watch had previously accused Samsung's suppliers in China of using child workers, leading the company to temporarily stop working with the supplier.