Waikato jockey Lisa Cropp was stood down from riding at Te Awamutu races yesterday after a drug test "irregularity".
Cropp, 44, was one of a number of jockeys asked to supply a random drug test and after the results were processed on course she was stood down from her remainingride.
Racing Integrity chief steward Ross Neal said Cropp's test was "not negative".
"That's the term drug agencies use when there is an irregularity."
Cropp became New Zealand's most famous drugs case in racing when she returned a urine sample positive to methamphetamine after riding Darci Brahma to victory at Te Rapa races in 2005.
She was subsequently disqualified for nine months and ordered to pay close to $100,000 in fines and costs.
When she received her licence back Cropp rode in Melbourne for a time, but announced her retirement, coming back to riding only 19 days before yesterday.
Cropp will not be permitted to ride until the end of any hearing resulting from yesterday's testing.
