CARLTON defender Jed Lamb has failed in his bid to overturn a striking fine at the AFL Tribunal, which incredibly deliberated for 36 minutes before finding him guilty.

After one of the longest deliberation periods at the AFL Tribunal this year, Lamb's fine will now be raised to $3000 as a result of his unsuccessful appeal.

Lamb had initially been offered a $2000 fine for striking Western Bulldogs star Marcus Bontempelli in the back during their clash on Sunday, with the incident graded by Match Review Officer Michael Christian as intentional, with low impact to the body.

Carlton made two points in its appeal, saying Lamb did not produce a striking action and that the contact made did not amount to negligible impact.

It also relied on the Bulldogs' medical report, which revealed that Bontempelli had pre-existing back pain.

Lamb's representative, Marcus Clarke QC, showed evidence of Bontempelli being in pain prior to the incident with Lamb. Combined with the Bulldogs' medical report, he argued that his injury added to the midfielder's reaction to being struck.

Clarke also played audio from Bontempelli's interview with RSN Radio on Tuesday morning, where he admitted to having back pain in the week prior to Sunday's match.

However, the AFL's legal representative, Jeff Gleeson QC, said the strike was sufficient enough to cause any player pain, regardless of their pre-existing injuries.

The Tribunal deliberated for an extended period, before upholding the initial grading.

Lamb was accompanied by Carlton's new footy boss Brad Lloyd at the AFL Tribunal hearing, as well as the outgoing Andrew McKay.