She said the situation had deteriorated since she made her name in the industry more than 25 years ago.
In an interview to be broadcast on Channel 4 News on Monday evening, the 43-year-old denied that she was accusing the industry of racism.
But she said: “I’m saying the act of not choosing models of colour is racist. So... we’re not calling them racist, we are saying the act is racist.”
Campbell has lent her voice to the Coalition, a group of fashion professionals who issued an open letter to Fashion Week councils in London, New York, Milan and Paris listing the designers that they said used only one or no black models in last season’s runway shows.
The British model said that during last year’s New York Fashion Week, just 6% of models were black and 9% Asian.
Adding that there had been no progress since she became famous, Campbell said: “When I started modelling, I did Yves Saint Laurent, I did...Versace. There was a great balance of models and colour.”
Campbell said the discrimination she suffered “made me stronger” but she added that “not all of the young models today are like that and not all of them are able to speak for themselves”.
She said of London Fashion Week, which has featured several appearances by Cara Delevingne on the catwalk: “I have faith in London ... because the British Fashion Council was the first fashion council to respond ... and it was a positive response.
“So I feel really optimistic about London. I think London is going to do the right thing and we are going to see a lot more models of colour on the runway (in London).”