The 37-year-old, who has appeared nearly 300 times for his country, tested positive during the Asia Cup in Bangladesh in October and has now been suspended.

According to the New Straits Times, the Malaysian Hockey Confederation (MHC) were informed about the failure in a letter from the International Hockey Federation.

The failed test was submitted after Malaysia's last group game against Oman on October 16, which they won 7-1.

They went on to finish as runners-up at the tournament, losing the final 2-1 to India.

"It was not a substance taken to improve nor enhance the performance of the athlete, but coincidentally the substance, though little, was found to be in his body, so the FIH will be taking action against S. Kumar," said MHC President Datuk Seri Subahan, as reported by the New Straits Times.

"We are well aware that Kumar is an experienced international who has amassed 295 caps playing for the country, and having undergone about 10 doping tests throughout his career, where he tested negative during previous doping tests.

"We strongly oppose doping, though we will have to go through the required process in place."

Sibutramine is an appetite suppressant which has been banned by the World Anti-Doping Agency.

Kumar has denied any deliberate attempt to cheat.

He will reportedly not request the opening of his B-sample with a hearing due for January. 

"I never take any outside supplements other than the ones that have been given by National Sports Institute," he said, according to Malay Mail.

"Logically, as a hockey player I do not need to lose weight. 

"So why do I need to take that substance?

"That doesn't make sense."