Punters left out of pocket by failed wagers will face credit checks.
Those losing the most are the most likely to be prevented from making wagers in the future under Government reforms to crack down on problem gambling.
Punters losing £2,000 within 90 days — equivalent to £23 a day — will be flagged as a risk and undergo extensive credit-probes, as will those who lose £1,000 in 24 hours.
Lighter checks will apply to those who lose £125 or more in a month, or £500 in a year.
There would also be a maximum stake of between £2 and £15 a spin on online slot games, with a £2 cap for the under-25s.
Betting firms would have to pay a new legal levy towards funding NHS help for problem gamblers.
The rate is yet to be fixed but minister Stuart Andrew said he’d be “very surprised” if it was under one per cent of company profits.
Action on “harmful” bonus bets, a review of the horse racing levy, and new powers for the Gambling Commission to tackle black market betting were also unveiled.
Culture Secretary Lucy Frazer told MPs: “When gambling becomes addiction, it can wreck lives. Shattered families, lost jobs, foreclosed homes, jail time, suicide.
“We need a new approach that recognises a flutter is one thing, unchecked addiction is another.”
Details of the action firms will take after credit checks will be detailed in a consultation.
Operators largely welcomed the Government White Paper, with Flutter boss Peter Jackson saying: “Whilst we need to review the detail, we believe proactive change will lead to a better future for our industry.”
But critics claimed the measures would drive gambling addicts on to the black market.
TV horse racing host Matt Chapman said: “Sending betters underground is the worst possible outcome.”