The amount of TV children watch should be rationed according to a "recommended daily allowance", an expert is due to tell MPs.
Dr Aric Sigman said the Government must take action to cut TV-watching among children as too much increases the risk of health and learning problems.
He wants to see parents given recommended daily amount guidelines, much as they are for salt intake, and said "screen media" was a major issue for public health.
Studies have shown excessive TV watching is linked to difficulty in sleeping, behavioural problems and increased obesity in children.
One long-term study, published in The Lancet medical journal in 2004, found children who watched more than two hours of television a day between the ages of five and 15 saw their health suffer years later.
Experts made the link between childhood viewing and raised cholesterol levels, obesity and smoking in adulthood.
Dr Sigman will urge the Government to advise parents on the issue and suggests children under three should watch no TV at all. He also believes there should be no TV sets in children's bedrooms and new mothers should be warned of the possible effects.
He rejected claims that setting down guidelines constitutes a "nanny state" and said: "Parents need an ideal reference point, even if they choose to ignore it or cannot adhere to it."
Dr Sigman, an associate fellow of the British Psychological Society and a member of the Institute of Biology, will voice his concerns at a Children and the Media conference at the House of Commons, organised by pressure group Mediawatch-UK.
