Powerful Milan fashion houses first resisted calls to copy the Spanish regulations, with Italian National Fashion Chamber head Mario Boselli saying in September that only "maybe one girl in a hundred" could be defined as too skinny.
But after Boselli, whose lobby represents big names like Armani, Versace and Prada, met Italian Youth Minister Giovanna Melandri this week, he agreed to work with the ministry on a self regulatory code of good practice.
"Italy has an important strategic role in world fashion so we have to send a strong signal," said Flaminia Spadone, an aide to the minister.
The manifesto will be launched before the Milan women's fashion week in February, a major event in the catwalk calendar.
"We'd like fashion houses, modelling agencies, photographers and everyone working in the fashion world to sign the charter," she said.
"It would be voluntary but professional bodies could decide to impose sanctions on people who don't sign, preventing them from taking part in fashion shows."
Boselli said the charter might require women to undergo medical checks for body weight, though it would also take into account factors like genetic influences on weight.
The use of underweight models promoting the ultra-slim look has held sway in much of world fashion since the 1990s, and was epitomised by British supermodel Kate Moss.
But it has come into sharp critical focus since the death of Brazilian model Ana Carolina Resto last month from complications derived from the slimming disease anorexia. There are calls for a return to the slim but more curvaceous models of the 1980s, like Cindy Crawford and Claudia Schiffer.
"We won't have a specific limit on body mass index as they do in Spain," said Boselli.
But Spadone said the ministry would ideally like to follow the Spanish example and impose a limit on the body mass index, which takes into account the model's height versus weight.
She said models who came under 18.5 on the index – the World Health Organisation's definition of underweight – should be banned from working for the sake of their own health.
"In the Third World, if someone has an index of less than 18.5, they send in humanitarian aide," she said.
with additional reporting by Sophie Hardach