Australian horses have been excluded from some of the most exhaustive and comprehensive international tests on the misuse of the outlawed cobalt chloride.

Analysts collectively agreed to not include Australian horses as they feared that it would skew the results after the discovery of the use of cobalt chloride in at least three states of Australia.

Fairfax Media understand horses from Australia were an unacceptable risk for the tests and analysts were concerned that cobalt abuse in this country could significantly bias the findings.

Their perception was subsequently proved correct after a string of cobalt positives in Harness Racing NSW that were investigated last year and which have resulted in 10 trainers being disqualified from the sport for long periods of time.