But Ms Gallagher said she was hopeful the federal government would agree to introduce national restrictions on junk food ads.

During the territory election campaign, the Greens promised to ''legislate to protect children from targeted junk food advertising through avenues such as prime time television, in cinemas, and on bus shelters.''

But the parliamentary power-sharing agreement between Labor and the Greens only refers to a commitment to ''work with other jurisdictions'' to implement a ban during children's television viewing hours.

Ms Gallagher said agreement from the Commonwealth would be required for a ban to go ahead.

''There are a range of health issues where it makes sense to work with other jurisdictions - and in particular the federal government - to develop a national approach to health policy matters,'' she said.

''The ACT government has consistently taken the position that it is not within the capacity of the ACT administration to legislate in this area and therefore advocacy to the Commonwealth government and agreement from them is required before any ban could be put in place.''

Ms Gallagher said that in accordance with the Labor-Greens agreement, she would purse the advertising issue, as well as other policies such as ''making water the drink of choice'' and promoting ''active living'' across all areas of government.

Television is regulated by the Commonwealth but some legal experts believed that the states could introduce restrictions on junk food advertising, provided that they were not inconsistent with federal laws.

The jurisdiction of the territories was not as clear, although the Obesity Policy Coalition believed the ACT may have the power to act.

The ACT's Self-Government Act prohibits the Legislative Assembly from legislating for, ''the classification of materials for the purposes of censorship.''

Voluntary industry codes impose some restrictions on junk food advertising during children's viewing hours.

Joanna Henryks, an assistant professor of advertising and marketing communication at the University of Canberra, said advertising restrictions could be one useful tool in the battle against childhood obesity.

''In and of itself it won't change things, but greater regulation is potentially part of the solution, by stopping pester power,'' she said.

Professor Elizabeth Handsley, president of the Australian Council on Children and the Media, said regulation of online food marketing aimed at children should also be examined.

''It's now moved way further onto other platforms. There's things like sports sponsorship that needs to be looked at, there's things like adver-gaming on the internet where food companies put a nice little game on the internet where kids get immersed in an advertising message for hours on end or as long as they play a game. All of those things needs to be looked at,'' Professor Handsley said.