The NBA lockout now shifts to the American courts after the players union decided on Monday it was time to "push back" and reject the latest offer from the owners.

In a high-stakes game, with the 2011-12 NBA season hanging in the balance, the players said they had no choice but to risk it all and move to disband their union and begin the process of filing an antitrust suit against the league.

"We understand the consequences of potentially missing the season; we understand the consequences that players could potentially face if things don't go our way, but it's a risk worth taking," union vice president Maurice Evans said. "It's the right move to do."

Billy Hunter, executive director of the union, said the union didn't like commissioner David Stern's ultimatum that if they didn't accept the latest proposal then they should brace for an even harsher one when, and if, talks resume.

Hunter added he thought the latest proposal from the owners was "extremely unfair" adding they are aware what this battle might cost them. That proposal called for a 72-game season, beginning December 15.

"This deal could have been done. It should have been done," Hunter said. "We've given and given and given, and they got to the place where they just reached for too much and the players decided to push back."

Players ignored Stern's warnings, choosing instead to blow up the union. That paved the way for a potentially lengthy lawsuit which could be filed in the next few days. It could also net them billions of dollars in damages.

The union filed their "notice of disclaimer" with the NBA head office in New York an hour before they held their news conference on Monday.

Hunter said the players would be represented in a class-action suit against the NBA by lawyers Jeffrey Kessler and David Boies -- who were on opposite sides of the National Football League labour dispute, Kessler working for the players, Boies for the league.

The NBA owners had already has filed a pre-emptive lawsuit seeking to prove the lockout is legal and contends that without a union that collectively bargained them, the players' guaranteed contracts could legally be voided.

The NBA's last work stoppage reduced the 1998-99 season to 50 games. So Tuesday will mark the 138th day of the current lockout.

The NBA players now find themselves headed down the same path as the NFL players who went through a 136-day lockout this year.

In its labour fight, NFL players tried to get the courts to overturn the lockout and let players get back to work. A Minnesota judge initially ruled in favour of the players, but then that ruling was put on hold by an American appeal court.

"Given the rulings that came down in the NFL case... right now the owners are not in a bad spot," said New York antitrust lawyer David Scupp.

"It could very well be that the players have an uphill battle toward getting that lockout enjoined. If they can do that, then it might swing things in their favour."

The two sides can remain negotiating during the decertification and legal wranglings so no one wants to write off the season just yet.

But in order for the NBA to have a 72-game season, Stern admitted the two sides would likely have had to come to terms on a new collective bargaining agreement within the next week. Now it appears Stern will move to cancel more games sooner than later.

The owners say they need fundamental changes to allow for a chance to make money and provide competitive balance for all teams. Their desire for a 50-50 split of basketball-related income, after players were guaranteed 57 percent under the old deal, meant owners would be receiving at least $280 million per year more from the players.

Stern's latest proposal also capped the maximum player salary at $20 million by 2013-14 and shrunk the maximum contract length to five years from six. Rookie contracts would also be reduced by 12 percent.