A ban on TV and radio adverts for casinos, betting shops and online gambling sites is to be scrapped.
The Salvation Army says it is "deeply concerned" by the move
The new rules will come into operation in September as part of the Gambling Act 2005.
Adverts will still be banned during shows aimed at under 18s - and anyone who appears to be under 25 cannot be shown gambling on TV or on radio.
Minister for Sport Richard Caborn said the government would monitor the changes and step in if problems arose.
Some forms of gambling are already exempt from the ban, including the National Lottery.
Spread betting can be promoted as an "investment activity" under Financial Services Authority rules, and bingo halls, football pools and amusement arcades can advertise as long as they adhere to guidelines.
From September, advertisers must stick to a set of rules designed to ensure they are "socially responsible". They must not, for example, depict gambling as a solution to debt.
Adverts must not show gamblers behaving in a way which is irresponsible or could lead to "financial, social or emotional harm".
And as with alcohol, anyone promoting gambling must not link it to sexual success or enhanced self-image.
Mr Caborn said the restrictions were needed to protect children and other vulnerable groups.
"They set out clearly what is and isn't acceptable advertising practice for all gambling operators, while making sure that the protection of children and vulnerable people is a central consideration of all advertising campaigns."
But he added: "If they are insufficient to ensure proper public protection, the government will consider using its additional powers to impose further restrictions."
The new rules were drawn up by the Committee of Advertising Practice (CAP) and the Broadcast Committee of Advertising Practice (BCAP).
The National Lottery
They will be policed by the Advertising Standards Authority and any breach could be referred to the Gambling Commission or the regulator Ofcom who could impose sanctions.
Nicola Crewe-Reade, from addiction counselling service GamCare, which is funded by the gambling industry, also backed the changes.
"We hope the outcome of these new standards will be to encourage people to see gambling as fun and entertaining rather than as a way of making your fortune," she told the BBC News website.
Professor Peter Collins, from the gambling studies centre at Salford University, said restrictions had worked in other countries such as South Africa, where all adverts must carry a warning about the dangers of gambling and a helpline number.
But some people would inevitably still be vulnerable, he said.
"They really do believe there is a person called Lady Luck who may smile on them this morning and get them out of all sorts of difficulties."
Captain Matt Spencer from the Salvation Army said he did not think gambling should be seen as a "normal leisure activity".
"Our fear is that more people will be drawn into an addiction which can be devastating for individuals, families and the communities in which they live," he added.