America’s four major television networks have joined forces to sue the broadcasting watchdog over rulings that shows were indecent.

They are arguing that several of the Federal Communications Commission’s decisions in March were wrong, and went beyond its authority.

ABC, CBS, NBC, Fox, and Hearst-Argyle Television Inc. issued a joint statement explaining their action. It said: "We strongly believe that the FCC rulings issued on March 15 that we are appealing today are unconstitutional and inconsistent with two decades of previous FCC decisions."

The problem arose particularly from instances of celebrities swearing on live television shows, such as the Billboard Music Awards. One of the recent decisions was against that programme, broadcast on Fox on December 9 2002, when Cher used an obscenity.

Others include an episode of The Early Show, episodes of ABC's NYPD Blue and two other music awards shows on Fox at fault over indecent language.

The networks’ statement adds: "In filing these court appeals we are seeking to overturn the FCC decisions that the broadcast of fleeting, isolated – and in some cases unintentional – words rendered these programs indecent."

Their case has the potential of sparking a wider debate on the FCC’s power over broadcasting. The networks say current rules are made for the time when there were few television and radio stations available. Now, they argue, with wider choice and censoring technology like the V-chip, they are unnecessary.

Much political opinion lies with the FCC, however.