Former Godolphin jockey James McDonald faces an anxious wait to learn if his attempt to downgrade an 18-month disqualification for a betting offence has been successful.

McDonald sat impassively through a two-hour hearing in front of the Racing NSW Appeals panel on Monday, speaking only to confirm his age, while counsel Bret Walker argued a two-year mandatory punishment was too severe for a jockey whose reputation had already been irreparably damaged.

The 25-year-old New Zealander, Sydney's reigning premier jockey, was disqualified for 18 months last December after admitting he placed a $1000 bet on his mount, the John O'Shea-trained colt Astern, at Randwick a year earlier.

He received a six-month discount for pleading guilty and co-operating with stewards after initially denying he had profited $4000 from a bet laid on his behalf by professional punter Anthony Gardiner.

Gardiner continues to distance himself from the investigation.

Walker submitted the mandatory two-year penalty - introduced after Damien Oliver was outed for 10 months for placing a $10,000 bet on a rival horse in a 2012 race he rode in - was not a fair starting point for McDonald's offence.

Walker said the two-year mandatory sentence - introduced in 2013 - was inflexible and there should be a distinction between betting on your own mount and backing a rival horse, raising the comparison with Oliver.

He argued McDonald's "casualness and carelessness' should not be subject to the same minimum punishment.

Walker lobbied for a 6-9 month suspension, a penalty that would enable McDonald, who he conceded would never again be considered a 'clean skin', to resume limited involvement in the industry.

Walker lodged character references that indicated McDonald had gained the respect of 'hard heads' in the industry, reiterated the jockey had donated his winnings to charity and said he would be willing to travel to regional centres to warn apprentices about the industry's pitfalls.

The three-member Appeals Panel, headed by Richard Beasley, is expected to deliver its decision late this week, or early next week

Racing NSW chief steward Marc Van Gestel argued a further reduction in penalty was not appropriate, because although McDonald co-operated, he originally made repeated denials.

Referring to an interview held between McDonald and Racing NSW stewards, Van Gestel said the jockey at one point said "I swear on my life" that he had not placed the bet.

Finally, 27 pages into the transcript, McDonald confessed: "Yeah, I did have a little bit on".

McDonald's disqualification expires on May 15, 2018.