A website to help parents complain about what campaigners have dubbed the "pornification" of children should be put in place within months,said.
The measure is among the recommendations of a Government-commissioned review of the sexualisation and commercialisation of young people carried out by Mothers' Union chief executive Reg Bailey.
Mr Cameron also backed moves to make it easier to block adult content on mobile phones, ban raunchy billboard posters near schools and bar the use of youngsters to market products.
And he said he would summon retailers, advertisers, broadcasters, magazine editors, video games and music industry chiefs and regulators for a summit in October to discuss progress.
Under the changes proposed by Mr Bailey, steamy pop videos would be restricted to older teens and later television slots and magazines featuring sexualised images covered up on shelves.
An option to request adult material be barred from any new home internet service, laptop or mobile phone should also be introduced and parents given more say in the TV watershed guidelines.
In response to demands for restrictions on inappropriate children's clothing - including lace lingerie and push-up bras - the British Retail Consortium launched stricter guidelines.
Nine stores - Asda, Debenhams, Argos, John Lewis, Next, Marks & Spencer, Peacocks, Sainsbury's and Tesco - have signed up with others being urged to participate.
Mr Cameron said he was particularly keen to see rapid progress on a centralised online tool for parents to report inappropriate material or products.
"This not only seems entirely sensible, but also relatively easy and simple to introduce. I see no reason why the website cannot be up and running in good time to get feedback from parents for our October meeting," he said.