Officials are looking at the possible link between the use of digital technologies and surging demand for mental health services.
Dr John Crawshaw told the Herald the link could be particularly strong for children and teenagers.
His comments come as the Ministry of Health releases new guidelines, discouraging any screen time for under-2s, and a daily limit of an hour for kids under 5.
"The science advice to the ministry is that early childhood and adolescence are times when the human brain is particularly malleable - for instance, we've long recognised that it can be dangerous for the brains of the young to be exposed to alcohol or drugs when they're so susceptible," Crawshaw said.
"The modern digital environment does offer an explosion of positive opportunities and connections for young people, both socially and in learning, but there's a danger of overexposure. So it's important that these are carefully managed.
"It would be foolish to ignore the potential impact of the digital dimension as an influence on mental health," Crawshaw said, adding he wanted to keep discussions on the topic going, both through the ministry's chief science adviser John Potter, and Sir Peter Gluckman, the Prime Minister's chief science adviser.
The country's mental health system has become an issue ahead of September's election.
Labour leader Andrew Little has pledged to make improving services a priority if in government, and a series of reports highlighting problems have been released, the latest a damning report from the Office of the Auditor-General on discharge procedures for patients who end up in hospital.
Budget 2017 allocated an extra $224m over four years for mental health services, through the social investment package. Cabinet will soon consider a new mental health and addiction strategy.
Crawshaw spoke to the Herald after appearing before Parliament's health select committee, which is considering its own review into mental health services.
The percentage of the population seen by a mental health specialist or secondary service has increased to 3.6 per cent, from 2.2 per cent in 2002/03.
Asked what was driving that increase, he said that was being investigated.
"New Zealand society is experiencing ... urbanisation and some of the pressures associated with that. Also the change in terms of digitisation, and the digital impacts on particularly our young people," he told the committee.
Martin Cocker, executive director of Netsafe, a not-for-profit focused on online safety, said it was early days in terms of research on how use of digital technology can affect mental health.
"It is on the horizon. We are starting to see researchers explore the sort-of mass effect of the technologies that we have picked up. The social and cultural impact of things like the almost ubiquitous use of social media.
"There are certainly people now saying, actually, maybe there are some negative effects from these technologies that we have been adopting."
That could range from being sat in front of a screen for too long to bullying and self-perception risks of social media.
"Bullying and harassment aren't a new phenomenon for society, but the movement online ... you feel as though you are never safe, so the bullying feels more relentless," Cocker said.
"And on social media things like Facebook tend to be a bit of a highlights package. There is more and more research done on what is the impact of essentially viewing all your friends' highlights packages, and then comparing it to your own actual life. And whether that makes you feel worse about your life than you would without it."
Results from a survey of almost 1500 14- to 24-year-olds by the Royal Society for Public Health in the United Kingdom were released last month. It asked respondents to rate five forms of social media on 14 different criteria of health, including anxiety, depression, loneliness and self-identity.
Instagram got the most negative score, particularly on feelings of anxiety, depression and loneliness, although respondents noted upsides including self-expression.
In response, Professor Simon Wessely, president of the Royal College of Psychiatrists, warned against "blaming the medium for the message", saying social media has as many benefits as negatives.
Cocker agreed, saying technology had many positives, including helping connect people and in some cases make them feel less alone. Mental health providers also use technology to get services to people.
"You can't turn back the clock, you can't undo digital technologies. We have to work out how to make the most of the opportunities they present and manage whatever challenges they throw up."
How much screen time?
• Discourage screen time for under-2s, and limit it to less than an hour a day for those aged up to 5.
• No more than two hours per day of recreational screen time for school-aged young people (aged 5 to 17 years).
Source: Ministry of Health guidelines.
Where to get help:
• Lifeline: 0800 543 354 (available 24/7)
• Suicide Crisis Helpline: 0508 828 865 (0508 TAUTOKO) (available 24/7)
• Youthline: 0800 376 633
• Kidsline: 0800 543 754 (available 24/7)
• Whatsup: 0800 942 8787 (1pm to 11pm)
• Depression helpline: 0800 111 757 (available 24/7)
• Rainbow Youth: (09) 376 4155
• Samaritans 0800 726 666
• If it is an emergency and you feel like you or someone else is at risk, call 111.