GAMBLING:Smartphone users will soon be able to gamble with real money on virtual slot machines, trying their luck with the swipe of an index finger.

Big Fish Games, which has Irish operations, is introducing a version of its gambling application Big Fish Casino with real-money betting in the UK, where it is legal, the Seattle-based company said.

It will arrive in Apple's App Store in the coming weeks, and Betable, a London-based partner of Big Fish, will process bets in the programme.

It is not yet known if the real-money betting version of the game will be available to Irish users, although a "play" version is available in the App Store.

Game developers are building digital versions of Las Vegas casinos as users of smartphones and tablets are expected to wager $100 billion annually on the devices by 2017, up from about $20 billion last year, estimates Juniper Research.

That potential payout has made developers eager to replace virtual currencies with real cash in apps, even though use in the US may be limited by gambling restrictions.

However, Big Fish may soon face competition from Zynga, the largest maker of social games, which last month said it plans to introduce real-money betting in the first half of 2013.

Restrictions on internet gambling in the US may also ease, as several states, including California, Nevada and New Jersey, are considering legislation to legalise the practice.