These included overtime in excess of local laws as well as fines for being late or absent from work.
However, it found no evidence of under-age workers at any of the suppliers.
The audit followed a report by China Labor Watch which alleged that it had evidence of long working hours and under-age workers.
"Samsung did not identify any instance of child labour during the audits after reviewing HR records of all workers aged below 18 and conducting face-to-face ID checks," the company said in statement.
The South Korean manufacturer said that it had asked all its suppliers to adopt a new hiring process immediately to address the problems identified.
It said that among other things, it had asked the suppliers to develop a longer term plan to resolve working hour practices by the end of this year and also to correct irregularities in labour contracts.
Samsung said it was reviewing practices at another 144 of its suppliers in China.
China Labor Watch (CLW), a New York-based campaign group, has published two reports about alleged breach of labour laws at factories of Samsung and its suppliers in China.
The first, published in August, alleged that it had found seven children - all of them are under the age of 16 - working at a factory of Samsung's supplier HEG Electronics.
Samsung had carried out an audit of that factory and said it did not find any evidence of child labour.
It was after that report Samsung announced that it would conduct an audit of 249 suppliers in China.
But just as Samsung promised to carry out the checks at its suppliers, CLW published another report alleging "illegal and inhumane violations" at eight Samsung factories in China.
CLW said it had found evidence of "forced and excessive overtime", "extensive labour contract violations", "abuse of underage workers", "lack of worker safety" and "severe discrimination based on age, gender, and individual characteristics unrelated to the job" among other breaches.
Samsung said that it had conducted regular checks as well as unannounced inspections of all its factories in China in October.
"Except the overtime issue, violations covered in the report are not in line with our knowledge," Samsung said.
It added that it would correct its working hours practices and meet the local guidelines by the end of 2014.
Samsung says an audit of 105 of its suppliers in China has identified "several instances of inadequate practices at the facilities".