Haynes received the maximum sentence available after pleading guilty to kicking Shoalhaven forward Mick Johnson in Saturday's match at Gerry Cappetta Oval.

The suspension is one of the heaviest handed down in the IRU's 56-year history.

"The judiciary expressed the view that it was the worst incident we've had before us, at least certainly in the four or five years I've been there," IRU judicial committee chairman Mark McDonald said.

"The maximum sentence was 18 months and that's what he got, but we'll be calling for a review of the sentencing process because the range probably should've been greater than 18 months.

"Our intention was to send the strongest possible message that we never want to see this sort of conduct repeated."

Haynes was sent off after the kicking incident, which occurred after a brawl between Johnson and Avondale's James Patrick. Johnson was lying on the ground when he was kicked.

Shoalhaven coach Paul Mulready described Haynes' actions as "cowardly" and "the sort of disgusting thing you might see in a street fight".

Avondale secretary David Brace yesterday said the club was "considering our options" in relation to an appeal.

Brace believes there was mitigating circumstances surrounding Haynes' actions.

"The issue is the severity of the sentence, because Scott made a submission to the judiciary that he'd been rucked in the head immediately prior to his transgression and the judiciary wasn't interested," Brace said.

"No-one at the club is denying what happened and we certainly don't condone it. It looked bad and it's something Scott regrets. But there was provocation and he was under duress. The Shoalhaven guy (Johnson) even apologised to our club captain after the game.

"There may yet be an appeal ... we're considering our options at the moment."

Avondale have until Wednesday to lodge an appeal.