Nine more kabaddi players have tested positive for banned substances during trials for next month's World Cup, pushing the number of failed tests up to 19 when combined with earlier results, the National Anti-Doping Agency (NADA) has said.

The 19 positive tests were recorded among 50 samples taken ahead of the tournament in Punjab and the players caught have already been provisionally suspended, NADA said in a statement late on Thursday.

The prohibited substances found in the nine new cases were steroids stanozolol, methendinone, trenbolone, drostanolone and nandrolone, and the stimulant phentermine.

Doping is a major problem in Indian sport and NADA has been forced to become more proactive as it deals with an increase in the number of cases, involving mainly athletes, wrestlers and weightlifters.

The selection trials for the Nov. 1-20 tournament was held at Ludhiana on Oct. 5 and NADA collected a total of 51 samples during the event.

Terming the situation alarming, NADA has decided that it would try and test every player participating at the World Cup, the agency's director general Rahul Bhatnagar said.

The alarming situation that has come to light in the wake of such a large number of positive cases, calls for stringent action on the part of the organisers of the event, Bhatnagar said in the statement,

Bhatnagar added that all World Cup participants should provide certification of a drug-free status before they can be allowed to compete.

Kabaddi, which requires no sophisticated equipment, is hugely popular in South Asia and was included in the 1990 Asian Games in Beijing for the first time as a regular discipline.

India has won all six gold medals in the Asian Games since its introduction and also won the women's event at the 2010 Guangzhou Games, where it was played for the first time.

The sport is played by two teams of seven members, in which a 'raider' enters the other half of the court to tag or wrestle opponents before returning 'home' while holding his breath and chanting 'kabaddi, kabaddi'.

India beat Pakistan to win the 2010 World Cup, a nine-team tournament which was also held in Punjab.