New Zealand mothers were particularly worried that their children's social skills were being hindered by the digital world, with 14 per cent saying they thought so.
However, John Cowan from The Parenting Place, said the study had used "meaningless comparisons".
"It's a bit like saying more kids can use smartphones than can drive trucks,'' he said. "I don't think I could tie my laces at age five.''
Research had yet to find any detrimental effects of smart device use among children, he said, because it was "too soon to say".
"But some research has shown that skills learned on iPads and things translate into real life skills," he said.
"The only thing I would get really concerned about is when it displaces the good things that we know that kids need _ physical activity, face-to-face language interaction and things like that. And if it's just being used as a cyber-sitter, then that's a concern.
"The other concern is that it opens them up later on, exposing their digital footprint to a world of predators or they damage their online reputation."
The research found that by the time children reach primary school the internet had already become ingrained in their lives.
In New Zealand, of the 92 per cent of the 6-9 age group using the internet, half were playing in virtual worlds such as Webkinz or Club Penguin, and 8 per cent were using Facebook, despite the social network having a minimum age policy of 13.
Mr Cowan pointed to research that showed children under 13 should not use social networking sites because they "do not have the emotional resilience or the technical savvy to keep themselves safe". But he said sites designed specifically for children were "overwhelmingly positive".
AVG security advisor, Michael McKinnon, described children's smartphone use as "a fairly divisive issue", saying there would "inevitably" be consequences in the future.
In particular he pointed to social networking, describing the percentage of 6- to 9-year-olds using Facebook as "alarming".
Children are not "emotionally equipped to handle all online experiences", he said, and he called on parents to take more responsibility for their kids' internet safety.
North Shore mother-of-one Sarah Winslade, 23, said she was happy with her son Cooper's iPad use, but admitted his competency had shocked and surprised her.
The 3-year-old can watch YouTube clips, use apps, take photographs and upload them to Instagram, as well as FaceTime his grandparents in San Francisco.
But Ms Winslade said she restricts Cooper's tablet usage to once a week, to ensure he still plays outdoors and with more traditional toys.
• By the age of 3-5, more children are able to navigate a smartphone (47 per cent globally and 58 per cent in NZ) than tie their shoes (14 per cent globally and 8 per cent in NZ) or swim unaided (23 per cent globally and 24 per cent in NZ).
• Of children aged 3-5, 57 per cent globally and 69 per cent in NZ can also operate at least one app on a smartphone or tablet _ an increase of 38 per cent since the same question was asked four years ago.
• 35 per cent of Kiwi kids under 5 knew who to call in an emergency
• Of the 92 per cent of Kiwi 6- to 9-year-olds using the internet, 50 per cent are playing in a kid's virtual world and 8 per cent are using Facebook.
• 14 per cent of New Zealand mothers viewed these `digital playgrounds' as hindering their child's social skills.
