(Adds details on recommendations, Iain Duncan Smith quote and background)
MILAN, Nov 4 (Reuters) - Shares in British gambling companies tumbled on Monday after a cross-party group of lawmakers called for a raft of measures to overhaul online casinos and protect vulnerable people.
The lawmakers called for limiting maximum stakes in online betting, similar to rules for high-speed slot machines where bets are restricted to 2 pounds, and banning the use of credit cards to gamble online.
In addition, the report http://www.grh-appg.com/latest-news called for a more responsible approach to advertising and restrictions on VIP accounts, which can involve offering more frequent gamblers bigger rewards.
The recommendations included calling for treatment of gambling addiction to be offered under the state-run National Health Service (NHS).
The Guardian newspaper said https://www.theguardian.com/society/2019/nov/03/call-for-radical-overhaul-of-online-casinos-after-far-reaching-inquiry Prime Minister Boris Johnson was thought to be sympathetic to calls for stricter regulation.
Shares in GVC, William Hill, 888 Holdings were trading between 4.7% and 8.7% lower by 1211 GMT.
"For too long, online gambling operators have exploited vulnerable gamblers to little or no retribution from the regulator," Conservative lawmaker Iain Duncan Smith said, urging the Gambling Commission to look into the issue in greater depth.
British betting companies are still reeling from the government's clamp down on high-speed slot machines, which critics have called the "crack cocaine" of gambling. The new rules cut the maximum stake allowed to 2 pounds from 100 pounds.
Bookmaker William Hill plans to close 700 British betting shops and GVC expects to shut about 900 outlets due to stricter rules that have forced firms to shift their focus to U.S. sports betting and online gaming.
The Gambling Related Harm All-Party Parliamentary Group, which posted the report, said it would publish a full report after final hearings.
(Reporting by Danilo Masoni and Tanishaa Nadkar; Editing by Louise Heavens and Edmund Blair)