England's Children's Commissioner is to be responsible for issues such as child obesity, bullying, school toilets and the portrayal of young people in the media, Margaret Hodge said this week.
The minister for children said a government amendment to legislation going through Parliament would clarify the new role, make it more powerful and give it a wider remit.
Ms Hodge said the move followed concerns in the House of Lords, where the Children Bill is being debated, about the future functions of the commissioner.
She told the Commons education select committee that she did not want the commissioner to regard him or herself as "the final court of appeal" in individual cases of abuse or neglect, but to look at the wider issues involving young people.
She assured MPs that the commissioner would be allowed to instigate reports and investigations of their own, and without reference to the Education Secretary. The office would also be independent of government.
After the hearing, Ms Hodge said her remarks had stemmed from her conversations with young people.
"When you talk to young people, they see themselves always being portrayed in the media as yobs, like the character Martin (Fowler) in EastEnders.
They say, 'We are not like that'," she said.
The commissioner would also look at facilities for young people because teenagers often complain that they have nowhere to go and nothing to do.
She said: "The state of school lavatories is another big issue for children, as is bullying. These are all things that can be looked at."
Ms Hodge told MPs: "I do not want the commissioner to see themselves as the final court of appeal on individual cases. This would be a terrible waste of the new capacity to promote children's interests. A report coming from the commissioner on things like child obesity, with a whole range of recommendations, would be extremely powerful."
The commissioner should also present an annual report to Parliament, like the chief inspector of schools, and be questioned on it by the select committee, she said.
"They can produce their own reports and these will not be doctored or vetted. They will be individual reports, published openly."
Ms Hodge said that while the department was "gearing up" to appoint the Children's Commissioner, this could not take place until the autumn, by which time the Bill would have become law.