Drug testing in sport will fail because the chance of catching doping cheats is so low that authorities can't make inroads into the problem, according to new research.

University of Adelaide researchers have examined worldwide data of positive doping tests from 93 different sports.

They found one single, random drug test was likely to catch a drug cheat just 2.9 per cent of the time.

For a 100 per cent strike rate, every athlete in the world would need to be drug tested up to 50 times a year - at a cost of at least $25,000 per athlete.

"The current system of anti-doping testing is inadequate to eliminate doping," said co-author of the research, Professor Maciej Henneberg.

"It appears that anti-doping policies are in place more for perception, to show that the right thing is being done.

"In practice ... the anti-doping system is doomed to fail."

Prof Henneberg said it would not be economically viable for drug testing to be completely effective.

"The annual cost of testing Germany's 4000 official athletes would exceed 84 million Euro ($A121 million)," he said.

"When you consider that the annual revenue for the German National Anti-Doping Association was only 4.5 million Euro ($A6.5 million) for the year ending 2010, that is a massive shortfall."

The study found if an athlete was tested 12 times a year, their odds of being caught was only 33 per cent - assuming they were continuously using drugs.

"But we know that athletes don't continuously use performance enhancing drugs, they have increasingly sophisticated techniques to avoid detection," Prof Henneberg said.