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.
"These sanctions are designed to include an element of rehabilitation and development as well as having consequences for the individual and team."
The Breach Notices propose Munster is fined $30,000 and suspended for 1 match, Smith is fined $15,000 and suspended for 1 match, Lewis is fined $4000 and suspended for 1 match and all three are required to complete education and training as directed by the NRL.
Walsh must also complete education and training as directed by the NRL.
All players have five working days to respond to the breach notices before any final penalties are announced.
Story first published on NRL.com