An irate Paea was overheard on FoxSports audio complaining to referee Jason Robinson about the Cronulla captain calling him a "black ****" after the two forwards clashed in the heat of the battle.
But Paea soon regained composure and chose not to make an official complaint when asked by the referee.
The two players shook hands and settled their differences after the match.
However, the NRL said today that racial vilification was a non-tolerable issue.
"While there is no on-field audio of the words used by Gallen and while Paea has declined to make a formal complaint under the racial vilification policy, there is little doubt from the on-field audio that there was a racial issue involved," an NRL statement read.
"It has also been confirmed that Gallen has since apologised for his on-field comments."
NRL boss David Gallop expressed concern over the incident through the statement.
"While the apology is certainly an important step in the right direction, there needs to be a clear recognition that racial vilification is not tolerated in rugby league," Gallop stated.
"This is not something that happens on a regular basis and it is not something that can be dismissed under the guise of what happens on the field stays on the field.
"I respect the fact that Mickey Paea has dealt with the issue one-to-one and that he wishes to move on.
"However, the area of racial vilification is also something that is bigger than two individuals, it involves a principle that we must support across all areas of the game.
"I don't believe racism is a part of rugby league and I don't suggest that these sort of comments represent a racist view, but I do believe that it is important everyone knows there are boundaries that simply can't be crossed.
"Excuses such as the heat of the moment or gamesmanship, when they are offered, simply don't change that fact."