Gambling losses in Australia, with a population of just 27 million, are estimated at Aus$25 (US$16 billion) billion a year.
Adverts enticing people to risk their cash are widespread on television, radio and billboards.
Slot machines known as "pokies" are installed in many pubs, too, drawing more to part with their money.
"Gambling advertising in Australia is out of control with one million gambling ads being aired on free-to-air television and radio in just one year," said a letter signed by more than 60 prominent Australians to Prime Minister Anthony Albanese and the opposition leader.
Signatories to the letter released at the weekend included former political, union, sports and faith leaders.
They urged Albanese's Labor government and the conservative opposition to agree to outlaw all gambling advertising within three years, in line with the recommendations of a 2023 report into gambling harm.
"Many Australians are alarmed about the proliferation of gambling advertising on our screens and the mounting losses through gambling," said former prime minister John Howard, who was among the signatories.
"I believe gambling losses are responsible for enormous harm throughout the community."
'Financial ruin'
Studies cited by the government put Australian gambling losses at Aus$25 billion a year, representing a global record per capita.
Even during a period of Covid-19 measures that closed many pubs, clubs and casinos in the 2020-2021 financial year, Australian state government statistics showed gambling losses exceeded Aus$24 billion.
"A total ban on all gambling advertising is essential to stop gambling companies targeting our children," said Alliance for Gambling Reform chief executive Martin Thomas.
"Any decision to simply cap advertising, or limit a blanket ban to only social media, would be a win for vested interests and leave Australians exposed to significant harm," Thomas said in a statement.
Besides the financial losses, the cost of inaction would be "mounting financial ruin, mental health problems, suicide, and the family violence that gambling can exacerbate", he said.
Australia's Nine Entertainment newspapers have said the government is expected to announce proposed legislation within weeks, possibly opting for limits instead of a total advertising ban.
Albanese said last week his government had engaged with "stakeholders" and was committed to "minimizing gambling harm" but declined to say whether an advertising ban was envisaged.