Twelve writers on America's Next Top Model have gone on strike after the show's executive producer refused to allow them to be represented by the WGA West guild.

The move comes just eight weeks before the show is due to form a key part of the new CW network's launch lineup. It is understood that only one episode of the new season has been completed so far.

The Hollywood Reporter reports that a number of writers picketed on Friday outside Top Model's production offices in Los Angeles, wearing T-shirts bearing slogans including "Tyra [Banks, the show's host and executive producer] is union. Why not me?"

The writers are seeking health cover, royalties, a pay increase, and writer credits (being currently listed as show producers).