When a five-year-old boy hurled his mother's smartphone across the room and smashed the device, it was the last straw for his parents.

It was the third time that Kenny (not his real name) had thrown the phone in a tantrum after being told to stop using it.

Despite his tender age, his family decided to take him to see a counsellor so that he could be weaned off his smartphone addiction.

They are not the only ones in Singapore facing such a problem.

Touch Cyber Wellness, which has been running cyber wellness education and counselling programmes for more than 15 years, said cases of excessive use of mobile devices have more than doubled in three years.

It handled 34 cases in 2015, 49 in 2016, and 76 last year.

On average, the centre's helplines receive about eight to 10 calls a week from parents seeking help and advice on their children's excessive use of mobile devices and social media.

Touch Cyber Wellness senior coach Michelle Lee told The New Paper: "As more young people have a phone, and at increasingly younger ages, they become more susceptible to phone addiction because they tend to lack self-regulation and consequential thinking."

In Kenny's case, his parents used games on the smartphone to pacify him during mealtimes. But the ploy backfired when he became addicted to them.

Mr Chong Ee Jay, a counsellor and manager at Touch Family Services, said Kenny was the youngest smartphone addict he had treated.

Mr Chong, 38, said: "Increasingly, smartphone addiction is intertwined with behavioural issues.

"This includes anti-social behaviour and ignoring of parents, so that they can have solo device time."

A recent study by global digital literacy group DQ Institute and Singtel found that Singapore children aged eight to 12 spend more time online for entertainment - 35 hours a week - compared to the global average of 32 hours.

The survey of 38,000 children in the age group across 29 countries also found that 54 per cent of them are exposed to cyber risks, such as cyber bullying, video game addiction, offline meeting and online sexual behaviour.

More worrying, those who own a mobile phone are more susceptible to online vulnerabilities, the study revealed.

They spend 15 more hours a week online than those without a mobile phone, and 70 per cent of them are exposed to cyber risk, compared with 45 per cent for those without a phone.

Despite the increase in such cases, Ms Jenny Liew, a counsellor at the National Addictions Management Service (Nams) in the Institute of Mental Health, said smartphone addiction is not officially recognised as a clinical disorder.

She said: "No one has actually sought help for smartphone addiction at Nams thus far. Right now, it is more of a cultural and social phenomenon than a clinical disorder, and almost everyone is glued to their smartphones these days."

Fortunately for Kenny, his smartphone dependence had a happy ending.

Touch Family Services' Mr Chong recommended a period of "digital detox", where Kenny was not allowed to use smartphones for two months and had to interact with his siblings and go outdoors instead.

The "time-out" resulted in two weeks of escalated tension before the boy's temper tantrums eased off by the end of the first month, and he started to enjoy family time with his siblings.

The last time Mr Chong heard from the family a few months ago, they were doing well.

"As parents, we need a long-term game plan in mind and adjust our approach when it comes to giving children smartphones," he said.