The 2011-12 National Basketball Association (NBA), US, has been thrown into doubt after a lockout was imposed on players until a new collective bargaining agreement is secured.

A dispute has arisen between the NBA and the National Basketball Players' Association in relation to an expiring agreement, which it is claimed as created a "broken system". Players will not be paid or be permitted to negotiate contracts during the lockout, while the team facilities will be unavailable the restrictions are lifted.

NBA deputy commissioner Adam Silver said: "The expiring collective bargaining agreement created a broken system that produced huge financial losses for our teams. "We need a sustainable business model that allows all 30 teams to be able to compete for a championship, fairly compensates our players, and provides teams, if well-managed, with an opportunity to be profitable."

The NBA lockout follows a similar dispute currently affecting the National Football League (NFL).