The NBPA's decision was in response to the NBA statement earlier on Wednesday that players who flop on the court in an effort to fool game referees into calling undeserved fouls on opposing players will be fined.
"The NBA is not permitted to unilaterally impose new economic discipline against the players without first bargaining with the union," NBPA Executive Director Billy Hunter said in a statement.
"We believe that any monetary penalty for an act of this type is inappropriate and without precedent in our sport or any other sport."
Beginning with the 2012-13 NBA season, the league said it will introduce an incremental system of penalties, starting with a warning for first offenders then a series of fines beginning at $5,000 and rising to $30,000 for a fifth violation.
A player who violates the rule six times or more would be subject to a possible increased fine and suspension.
According to the league, flopping will be defined as any physical act that appears to have been intended to cause the referees to call a foul on another player.
"Flops have no place in our game - they either fool referees into calling undeserved fouls or fool fans into thinking the referees missed a foul call," NBA Executive Vice President of Basketball Operations Stu Jackson said.
"Accordingly, both the Board of Governors and the Competition Committee felt strongly that any player who the league determines, following video review, to have committed a flop should - after a warning - be given an automatic penalty."
- Sports & Recreation