NORTH Melbourne vice-captain Drew Petrie has joined a chorus of voices calling on the AFL to overhaul its contentious Match Review Panel.

The MRP has come under fire in recent weeks for some inconsistent adjudications, in particular the two-match ban handed to Adelaide's Shaun McKernan for elbowing West Coast's Brad Sheppard.

Writing in the Ballarat Courier, Petrie questioned the legitimacy of the system.

"I don’t understand how it’s been allowed to get this bad and this disappointing," Petrie wrote.

"Every week, we are left dumbfounded by its findings and the system is having a direct impact on the careers of players."

Petrie described the ban handed to McKernan as "appalling", but labeled the MRP's finding as "more shocking".

The panel judged that McKernan's conduct was reckless, rather than intentional.

But Petrie said McKernan's actions should have earned him more than a fortnight on the sidelines.

Petrie compared McKernan's penalty to that of teammates Lindsay Thomas and Jack Ziebell.

Thomas received a two-match ban for what Petrie labelled a "soft headbutt" on Greater Western Sydney's Jacob Townsend in round 14, while Ziebell was given a three-match suspension for a hit on Adelaide's Jarryd Lyons in round nine.

Ziebell's ban was affected by the loading and the carry-over points he still had to his name from a similar case last season.

Just this week, Petrie's coach Brad Scott questioned the value of the points loading system by directly referring to the McKernan case.

Petrie argued carry-over points should only apply to consistent offenders, or "players that play against the spirit of the game and go out of their way to injure their opponents".

Petrie wrote that the length of both Thomas' and Ziebell's suspensions did not fit the crime, when compared to McKernan's ban.

"Jack Ziebell has already missed 10 games through suspension in just five years of AFL football," Petrie wrote.

"That’s pretty much half a season for one of the hardest and fairest ball players I’ve ever run out onto the ground with." 

Ben Guthrie is a reporter for AFL Media. Follow him on Twitter: @AFL_BenGuthrie