The off-contract playmaker can accept a $1600 fine with an early guilty plea after he was sin-binned and reported for contrary conduct as the players were heading to the sheds.

Teammate Dylan Napa (high tackle), Wests Tigers' Mikaele Thomas (high tackle) and Penrith hooker Api Koroisau (dangerous contact) can also accept fines after they were placed on report in Sunday's action.

Cronulla prop Aiden Tolman will miss a week, opting for an early guilty plea after he was charged for a careless high tackle on Canberra's rookie fullback Xavier Savage.

Bulldogs coach Trent Barrett was perplexed after watching his young half lose his cool, having helped the cellar dwellers build a surprise lead over South Sydney.

Walker and Lewis had words as the players were exiting the arena, before the Bulldogs five-eighth took his opposite number to the ground and sparked a melee.

The off-contract playmaker was then called back onto the field by referee Ben Cummins, and sin-binned for the start of the second half.

South Sydney scored eight points while he was off the field, which ended up being the final margin.

"I didn't know you could get 10 minutes in the walking off at halftime," Barrett said.

"He didn't hit him or anything but obviously something's happened."

Walker didn't elaborate when asked by Fox League after the game what had prompted the incident, only to say "what happens on the footy field stays on there".

Gold Coast pair Kevin Proctor and Patrick Herbert accepted fines for their dangerous lifting tackle of Isaiah Papalii, as did North Queensland's Shane Wright and Melbourne's Chris Lewis.

Australian Associated Press