Victoria Beckham has argued that many slim catwalk models are ''naturally thin'' and shouldn't be discriminated against.

Victoria Beckham has defended the use of size zero models.

The former Spice Girl-turned-fashion designer insists many girls on the runways do not starve themselves and instead have a naturally small body shape.

She said: "Most of these girls are naturally thin. And I don't think we should be discriminating against someone because they are too thin or too curvy or too large or whatever it is.

"I had a casting last week and had some terribly thin girls come in and it wouldn't have worked."

Victoria - who recently unveiled her fourth collection of dresses during New York Fashion Week - has signed up for the Health is Beauty campaign by the CFDA (Council of Fashion Designers of America), and believes designers are beginning to change who they cast as models.

She told US TV show 'The View': "The CFDA have reached out to designers, stylists and casting directors not to work with underage models, girls that are too thin and to be more ethnically aware.

"The campaign the CFDA has launched is called Health is Beauty and they are definitely encouraging designers to work with healthier sized models."

Victoria's designs have been worn by a wide variety of celebrities since her debut fashion range in 2008, including Heidi Klum, Madonna, Mary J. Blige, Elle Macpherson and Jennifer Lopez.