SECONDARY 1 student Calvin Tee spends whole afternoons playing three different online games at any one time because he is bored at home.

'I like the fact that my hero gets stronger and I get to meet other people. And there is nothing else to do,' says the bespectacled 13-year-old.

But he is quick to add: 'I play only during the holidays and sometimes during weekends of the school term.'

While youngsters like Calvin find nothing wrong with playing online games, psychologists and youth workers worry about the potential harm these games may do to children.

Gaming is one of the most popular pastimes for young people and children here.

A 2004 report by research firm IDC put the number of gamers here at over a million, while a 2005 survey showed that four in five aged between 15 and 25 play computer games.

But the fun and games come with a dark side.

One worry is that through these interactive online games, children may meet the wrong kinds of people and pick up undesirable habits or behaviour from them.

National Institute of Education's Associate Professor Angeline Khoo, who leads a research project on computer games, recalls meeting a 15-year-old girl online who said she was being sexually harassed by a male gamer.

'Whenever she logged on, he was there and would send her lewd messages,' says Prof Khoo. 'She didn't know how to deal with it and asked herself whether she was responsible for leading him on.'

Eventually, the traumatised girl reported him to the game administrators and he was banned from the game.

Says Prof Khoo: 'Parents have to get over the perception that games are just games. It may be virtual, but it's a real experience for the child.'

The dangers of online gaming are also a key concern for welfare organisation Touch Community Service, which runs programmes to help game addicts.

The organisation's manager, Mr Poh Yeang Cherng, notes that swearing and resorting to violence - like ganging up on other players they dislike - to solve problems are common- place behaviour in games.

These include popular online games like Runescape and Ragnarok and Defence Of The Ancients.

'Some parents get shocked when their 12- or 13-year-old suddenly uses vulgar language on them. Well, they've probably been exposed to it for years online,' says Mr Poh.

Its dangers, he says, are serious enough to make gaming one of the biggest threats of the digital age.

'Whole generations of kids are brought up on this diet of virtual reality, which may change them, make them disconnected from parents and the real world,' says Mr Poh.

The impact of such interactive digital media (IDM) is not lost on the Government, even as it sets aside $500 million to develop the industry.

Minister for Information, Communications and the Arts Lee Boon Yang said in a speech this week that new media 'will have powerful transformational impact on society'.

'For example, the impact of IDM on a child's mental development, reflexes, attitudes and communication skills will have a bearing on how we harness IDM for educational purposes and manage the increasing exposure to IDM among our children,' he said.

In some extreme cases, psychologists say that children have become pathologically addicted to computer games, which results in them neglecting their studies and compromising personal relationships with their parents.

The number of addiction cases is rising. Five years ago, the Institute of Mental Health admitted one young person for gaming addiction, compared to 12 last year.

Touch Community itself has handled about 50 cases since it opened its new 'cyber- wellness' centre last August, reveals Mr Poh. 'All of them started playing games when they were very young, in primary school or earlier.'

He believes it is a bad idea to introduce the Internet to children who have not started primary school, as many games are designed to attract the attention of the very young, and they progress rapidly to other games.

But if they must, parents must guide the child, says Mr Poh.

Another solution, suggests Prof Khoo, is for parents to make sure their children hang out online with the same friends they have in real life. 'That way they look out for each other and can help enforce good gaming habits, like playing for fixed hours,' she says.

Housewife Irene Tan, 44, and her husband David Tan, 47, a manager in an IT company, have adopted such an approach.

Mr Tan makes an effort to find out what games his son is playing, and visits technology websites like CNet and Yahoo to keep abreast of the latest trends.

To make sure their 13-year-old son Joel does not get addicted to games, they place their two computers where they can see what their three teenage children are doing online and limit the time spent in front of the screen.

Mrs Tan also relies on good old maternal instincts: 'When he gets moody without the computer, that's when I know its time for him to get out of the house to play football with his friends.'