Queensland apprentice Zoe White has been suspended for a month after returning a positive urine sample to a banned appetite suppressant.

Rockhampton-based White was the most successful apprentice In Queensland last season and transferred to premier trainer Tony Gollan last year.

She later went to Billy and Dale Healy at the Sunshine Coast but struggled for rides leading to her returning to central Queensland last month.

Stewards charged her with returning a positive in a urine sample taken at Mackay races on March 27.

She returned a positive to Phentermine which is listed as a banned anorectic substance and is often used in diet pills.

White pleaded guilty and was suspended four weeks backdated to April 13 when she voluntarily stood down.