Jamaica's most senior drug tester says the country's recent rash of failed tests might be the "tip of an iceberg".
Dr Paul Wright told the BBC that the Caribbean island's anti-doping regime had been woefully short of the international standards required.
His comments come a week after the World Anti-Doping Agency visited Jamaica to investigate claims that the country's athletes were not being tested rigorously enough.
Former Jamaican Anti-Doping Commission executive director Renee Anne Shirley sparked the crisis when she said the agency conducted just one out-of-competition test in the six months leading up to the 2012 Olympic Games in London.
Her criticisms, made in an article in Sports Illustrated, followed a series of adverse findings involving Jamaican track and field athletes.
Asafa Powell, the former 100m world record holder, was the biggest name to test positive, but four others including Powell's training partner - the Olympic relay gold medallist Sherone Simpson - also failed tests at the country's national trials in June.
Both Powell and Simpson claim that they took supplements that might have been contaminated with the banned stimulant Oxilofrine.
Wada officials are due to discuss their visit to Jamaica at an executive board meeting in Johannesburg on Tuesday and could make a series of recommendations to improve the country's anti-doping policies.
But Dr Wright - a senior doping control officer with Jadco who has 30 years of experience of drug testing in sport - is concerned that Wada's intervention will not lead to the sweeping changes required to give the world confidence in Jamaican sport.
And he said the sudden surge of athletes failing tests at the country's national trials in June had left him fearing the worst.
"The results are not good," he told the BBC. "This year alone the results really point the finger.
"Remember, all of these results except one were caught by Jadco. The problem is these people were tested positive in competition. What that means is months before you know the date of the test and the approximate time of the test.
"So if you fail an in-competition test you haven't only failed a drugs test, you have failed an IQ test.
"This could be the tip of the iceberg to have so many positives coming in competition.
"What is going to convince me is if there is an out-of-competition test that's unannounced, that includes blood testing and which tests for EPO. Then we can hold up our heads high and say we know there's nothing."
But the head of the Jamaican Olympic Association Mike Fennell dismissed Dr Wright's concerns, saying he was "being dramatic".
"I think that's massively overstating it," Fennell said. "There's no evidence to suggest that it's the tip of the iceberg."
Although Dr Wright met with Wada officials during their visit, he was critical, saying they did not spend enough time on the ground in Jamaica.
"I have a personal problem in what you can do in 12 hours," he said. "They really came late Monday evening and left first flight Wednesday morning. So they were only really here on Tuesday. And four hours of that was at a dinner function with the Prime Minister.
"It's not enough. Remember it was explained as an extraordinary audit. I would have loved them to have been here for a week, to have got answers to every question, to be able to question people who knew what was happening.
"Their intervention has led to the promise of change. If the promises are kept then we will get there."
Following Wada's visit, the Jamaican Minister for Sport Natalie Neita Headley vowed to pump more money in to testing to boost the current annual budget of just over £380,000.
That funding - with the help of additional money from Wada - would be used to hire more senior executives to run the anti-doping programme and to hire and train additional drug testers.
Mrs Headley told the BBC that she was currently hiring two extra drug testers, taking the total number of doping control officers to six.
She also vowed to increase the number of tests conducted by Jadco from 300 this year to 400 in 2014. And she said the commission was ready to start blood testing its athletes.
But, while Mrs Headley acknowledged there was a lot of work to be done, she said claims that Jamaica's top athletes had not been tested enough were wrong.
She said: "Our athletes, as confirmed by the IAAF, were the most tested in the world of athletics, so to say your athletes weren't tested is not exactly true.
"I would recognise that the events of the last couple of months would have harmed us tremendously. I recognise that.
"I also recognise that what is important is that the country puts all of what is needed in place to beef up a system, bolster your system that where there might be weaknesses you strengthen, where there might be any difficulties that you remove those difficulties.
"Though we are experiencing turbulent economic times, the budget of Jadco was increased this year unlike many other areas."
Six-time Olympic gold medallist Usain Bolt has said he wants to help restore faith in the sport after failed drug tests by fellow Jamaican athletes
Jadco has so far carried out 286 tests in 2013 - both in and out of competition. These are in addition to the tests conducted by the IAAF on a pool of 19 elite Jamaican athletes. These tests have taken place in competitions around the world but mainly in Europe and out of competition in the run up to the Moscow World Championships in August.
Sports officials in Jamaica insist that, while their own testing regime needs to improve, there are no reasons to doubt the performances of top stars like triple Olympic champions Usain Bolt and Shelly-Ann Fraser-Price.
Jamaican Olympic chief Fennell said he believed some of the positive tests had been caused by contaminated food supplements.
"There is a problem worldwide with the use of supplements," said Fennell. "The whole world is induced to use supplements for one thing or another.
"Athletes are no different. This is not with a view to cheating and I would put my head on the block and say our athletes do not set out to cheat.
"We do have rigorous testing. If you look at the record for this year you will see our testing record is amazing. Those of our top athletes are on the registered international programmes.
"More can be done and you tell me what country in the world where more cannot be done. A country like Jamaica has economic problems and we are doing extremely well with the resources we have but there's always room for more and we have to make sure we are up to speed."
One of Jamaica's leading sprinters, Nesta Carter, said athletes understood that the events of the last few months had put him and his team-mates in the spotlight.
"I understand why people pay more attention to Jamaica," said Carter, who won an individual bronze medal in the 100m in Moscow in August to add to his sprint relay gold from the London Olympics.
"It was the same when the US dominated. People said they were on drugs and should be tested. That's a part of the sport and we have to accept that. It's going to hurt fans and athletes because no-one wants to be associated with what's going on.
"It's kind of hard to see your fellow mates and people keep pointing the fingers at them and saying they are on drugs when they are not - so you just have to stay clean and do the right thing."