Walsh is facing a $5000 fine and two-match suspension while Smith, Munster and Lewis have had one-game bans and fines varying in accordance with their salary proposed.
NRL CEO Andrew Abdo said the players in question had let everyone down with their alleged actions.
"I understand that players have endured a long season under strict protocols. However, there is no excuse for the behaviour we have seen over the past week. The players have let themselves, their clubs and the rugby league community down," he said in a statement.