Racing Victoria stewards are investigating a positive swab returned by the stayer Anudjawun before a race he was unplaced in last month.

The Shaun Dwyer-trained Anudjawun broke through for the second win of his career, and first in three and a half years, at Moonee Valley last Saturday.

Stewards reported the gelding returned a positive pre-race urine sample to the non-steroidal anti-inflammatory ibuprofen before his ninth placing in a 2400m race at Caulfield on October 16.

Dwyer has been told of the positive swab and stewards are continuing their investigations.