Jumps jockey Rob David has been suspended for four months for failing to provide a urine sample at the Warrnambool carnival.

David was down to ride Mannertone in Wednesday's novice steeplechase but was replaced by Racing Victoria stewards after failing to provide a medical clearance following a fall at Oakbank on April 20.

After forgoing Wednesday's ride, David left the course without providing the urine sample.

At the completion of an inquiry on Thursday, David was suspended with immediate effect from all riding duties.

David was to provide a urine sample on Thursday and, if clear, he can return to riding trackwork, but will remain banned from riding in races.