Conservative leader David Cameron has called for an end to the "inappropriate sexualisation" of children.
Parents should be able to complain via a specially set-up website about offensive marketing tactics used by companies, he said.
Mr Cameron also told the BBC that firms which flout the rules should not be allowed to bid for government contracts for three years.
Such moves were needed to stop children being "bombarded", he added.
In 2008, Woolworths withdrew a girls' bedroom furniture range called Lolita - the same name as the 1955 Vladimir Nabokov novel about a man's sexual obsession with his 12-year-old stepdaughter.
Supermarkets have been criticised for selling padded bras and pole-dancing kits aimed at children.
And some teachers have called for girls' magazines to be given age ratings, arguing they "glamorise" sexual promiscuity.
Mr Cameron said: "It's time for action. As parents we all worry about our children growing up too fast and missing out on their childhood."
He added: "We cannot shield kids from the modern world and no-one would try, but we can try to stop them having inappropriate things put in front of them from an early age."
Mr Cameron told BBC Radio 4's Woman's Hour: "A lot of parents feel they are engaged in a kind of struggle to try to bring up our kids.
"We want to let them see the world as it is but not be bombarded by the wrong sort of images from an early age. We've all read stories about padded bras and Lolita beds. There are some worries."
The Tory leader revealed he had stopped his daughter from listening to pop singer Lily Allen because he was concerned some of her lyrics were "unsuitable" for a six-year old.
'Tough new rules'
He said the Advertising Standards Agency should get greater powers to deal with inappropriate marketing aimed at children - something the government says it is also working towards.
Children's Secretary Ed Balls said he had raised the issue in the Children's Plan two years ago, adding it was "good to have David Cameron's support because this is something which concerns all parents and is not an issue for party politics".
He said: "We have already acted to protect children from the irresponsible advertising of a wide range of products, including tough new rules restricting the advertising of unhealthy foods to children and the use of celebrities and cartoon characters to market them."
A government-commissioned report by psychologist Dr Linda Papadopoulos on the sexualisation of young people is due to be published in the next few days.
Penny Nicholls, director of children and young people at the Children's Society, said: "We know from our research that commercial pressures towards premature sexualisation, and unprincipled advertising, are damaging children's well-being.
"The evidence shows that adults feel children are more materialistic than in past generations.
"Children themselves tell us that they value family and friends above money, but feel under pressure to keep up with the latest trends.
"We need a significant change at the heart of society, where adults stand up for better values."