A north Queensland apprentice jockey has been suspended for six months for failing a breath test at trackwork.

Queensland Racing Integrity Commission officers conducted a snap check on riders at Cairns on October 30 and found Amanda Thomson to be in excess of the permitted threshold of .02.

Thomson's licence was suspended from the day she was stood down on October 30 until April 30.

One month will be wholly suspended for a period of two years on the provision she confirms she has completed a drug and alcohol course.

Thomson will also be required to provide a clear urine and drug test before her licence is re-instated.

Thomson pleaded guilty to the charge and stewards accepted her explanation for not attending her scheduled inquiry on Sunday with no further action taken.