Consumer groups around the world have urged food and drink manufacturers to further curb their marketing of junk food in a fresh bid to combat child obesity.

Consumers International, an NGO that represents consumer bodies in 115 countries, and the International Obesity TaskForce (IOTF) have drawn up a code for marketing products high in fats, sugar and salt (HFSS).

The proposed code, which was launched to coincide with World Consumer Rights Day on Saturday (15 March), would require "complete restrictions" on the promotion of junk food to children on the Internet.

The code would also see a ban on all advertising of junk food to children under 16 on television up to a 9pm watershed.

Prof Philip James, chair of the IOTF, said: "We challenge the giants of the food and beverage industry to throw their weight behind this code and demonstrate that they really do want to be part of the solution and no longer part of the problem."

Prof Arne Astrup, president of the International Association for the Study of Obesity (IASO), said he backed the "tough new measures".

"The time has come for all concerned to recognise that an international code, enforceable in law, is the best way forward," Prof Astrup said. "Voluntary measures and individual pledges from some companies offer inadequate protection when children are being targeted on the Internet, by mobile phone as well as via television, and especially in developing countries where these kinds of calorie-dense foods can have a devastating impact on children's health."

In the UK, legal restrictions on marketing fall short of a watershed, with ads promoting HFSS products banned from airing in and around programmes aimed at under-16s.

The UK's Food and Drink Federation said restricting advertising was "not the silver bullet" to solving child obesity.

"Industry is undertaking a wide range of initiatives to tackle the wider issue of health and wellbeing of consumers - for example, reformulating products and providing clear nutrition labelling," the FDF told just-food.

"As far as marketing in the UK is concerned, we are now one of the most heavily regulated markets in Europe. As a result the marketing landscape has dramatically changed recently - for example in addition to the new regulations, many of our leading member companies are developing new codes of practice or strengthening their existing ones. These codes of practice apply to products popular with children, and the codes are implemented globally."