In addition, Aegis, which includes Carat and Vizeum, has been involved in a wrangle over its TV airtime deal with five and the multichannel sales house ids, which sells for the Flextech channels Living TV, Bravo, Trouble and UKTV Gold, among others.
However, a spokeswoman for ids said: "We are more than happy with our relationship with Aegis."
It is understood that negotiations between ZenithOptimedia, which negotiates TV airtime for L'Oreal, and ITV Sales have reached an impasse, although L'Oreal advertising is still on air across ITV Digital.
ITV1 is said to be unaffected by the dispute.
A spokesman for ZenithOptimedia said: "We are still in negotiations with ITV and have not concluded any deals. We are negotiating our annual agency deals for all of our clients with ITV. We are not satisfied with what we are getting back from them and the matter is still being discussed."
No-one at ITV Sales would comment on the news.
A similar stand-off between WPP's Group M and ITV over its digital channels developed earlier this year but, according to insiders, a deal is close to being finalised.
Traditionally, agencies tie up their deals with broadcasters before the end of January, and most agreements for the calendar year have already been concluded.