The response from three of the most powerful chocolate producers in the world comes after Oxfam released a hard-hitting campaign that calls for equality for women coca producers.
The ad, which has been created by UK digital agency Code Computerlove, is running across 12 countries.
It begins as a typical chocolate ad and features a beautiful woman eating a bar of a chocolate, played out to sensual music. Then suddenly the ad adopts a different tone, the music stops and the ad addresses the issue of the inequality faced by woman coca growers.
The ad states: "When it comes to the women who grow their cocoa. The truth: hunger, inequality, unfair pay."
Mars, defending its policy, said: "Mars takes a comprehensive approach to this issue, with a strong focus on the entire farming community specifically in the area of coca sustainability. Our leadership has had a positive impact on the women, children and families of smallholder farms.
"Oxfam highlights important issues in their report and we look forward to working with them to address these critical issues."
Nestle said: "[It was] fully committed to further improving the livelihoods of small famers.
"We will support the efforts of Oxfam and other NGOs to make progress toward a sustainable food system, and we believe that a cooperative approach by civil society, government and business is required to bring this about."
Mondelez said: "Empowering women and encouraging female entrepreneurs is at the heart of our Cocoa Life initiative. One of its objectives is to empower cocoa farming families to create the kind of communities they and their children want to live in, and promotingr women's empowrment is central to this."Oxfam has also produced a league table that ranks the ethical performance of the world's 10 biggest food and drink companies. Brands mentioned include Nestle, Unilever and Coca-Cola.