Food makers operating in New Zealand face a new code overseeing how they advertise their products in the country.

New Zealand's Advertising Standards Authority, a body that promotes "self-regulation" in advertising, has unveiled a set of guidelines after a year-long review.

The 26-page Children's Code for Advertising Food lists a series of guidelines to which food makers must adhere including: that ads should not encourage children to consume in excess; and that ads should not "undermine" New Zealand government guidelines on food and nutrition for kids.

The advertising code also stipulates that "persons or characters well-known to children" should not be used to endorse food high in fat, salt and sugar.

The advertising watchdog admitted that, during consultation for the new code, some stakeholders made "serious and sincere concerns" about the "volume, timing and placement" of ads.

However, the watchdog said existing guidelines brought in by broadcasters in New Zealand had brought in "a number of limits" on advertising played during children's programmes.

It said the broadcasters' guidelines also included a "Children's Food" rating that "restricted" products high in fat, salt or sugar being advertised around children's progammes.

The code stated: "The panel considers that the introduction of the new Children’s Code for Advertising Food, which will impact on the overall content of advertising that influences children is the best way to address these concerns at this time."