The British supermodel, 42, has reportedly fallen out with the 24-year-old Canadian beauty on the set of their new modelling reality TV series 'The Face' - on which they are responsible for ''moulding, nurturing and transforming'' aspiring catwalk queens - leaving the show's host Nigel Barker to act as a mediator.
A source told the New York Post's Page Six: ''Nigel is the only one who gets along with everyone. He's been left as the host and the referee. You've got three models, all at different stages of their careers and different ages, and they are really not getting along. It's a competition show, and none of them are used to losing.''
Another source revealed: ''Naomi doesn't have to have a reason not to like somebody. She just doesn't like certain people.
''There were some issues with Coco being on time and Naomi not being on time and Coco getting annoyed. Coco's a Jehovah's Witness, and she believes in being correct and polite and being on time. She doesn't drink. She's super straight-laced. So it's been a real mess between [Coco and Naomi].''
Former 'America's Next Top Model' judge Nigel was reportedly overheard discussing the model's catfight at a charity benefit in New York hotspot Pink Elephant.
Model Karolina Kurkova, who will also appear as a coach on the new Oxygen show which will makes its US debut in February, is said to be trying not to get involved in the fight.
The insider said: ''Karolina knows how to deal with Naomi. She's known her for a longer time. Coco clearly knows Naomi doesn't like her. Naomi's tough. If you are not kissing her ass, you are dead.''
Naomi hinted at the spat on Twitter yesterday (14.12.12) when she wrote: ''I don't need a certain number of friends, just a number of friends I can be certain of.''