A "rigorous verification of age" process for young people purchasing phones and accessing apps is required, Education Minister Norma Foley has said.
Ms Foley warned that it is "far too easy" for children to access phones and has stressed that social media companies need to fully enforce rules that require them to get the parental consent of any user under the age of 16.
Ms Foley said she is not anti-phone, but ensuring providers play a strong role in age verification is an issue that her department is pursuing.
It comes after Ms Foley recently received Cabinet approval for new guidelines that encourage parents not to purchase smartphones for primary school children.
Raising concerns around the type of material children can be exposed to on smartphones, Ms Foley said: "I believe even the purchase of the phone in the first place, that there should be a rigorous verification of age, beyond a shadow of a doubt, there needs to be rigorous enforcement of age verification.
"I think it's possibly far too easy for young people to access a phone, and I think much more rigor needs to be enforced there."
The Growing Up in Ireland survey has found that 54% of nine-year-olds now own a mobile phone.
In an interview with the Irish Examiner, Ms Foley said there isn't a "campaign against phones" as she understands parents often want to maintain contact with children, adding: "There's no issue with the old Nokia standard kind of phone that was in existence".
"What we're really talking about is the smartphone and we're talking about, I suppose, the content in terms of social media that can be made available to young people that is not appropriate to young people.
"A stronger body of work around age verification is required there," she said.
Asked about what age she feels is appropriate for smartphone usage and having access to online apps, Ms Foley said: "Currently the digital age of consent would be 16.
"I need to be confident that that has been enforced as it should be enforced. That would be a good start."
The digital age of consent is the minimum age a user must be before social media and internet companies can collect, process, and store their data.
Social media companies and other online sites must obtain parental consent to collect the personal data of anyone under that age.
"In terms of the providers, I think we have to be very clear as well that they have a very strong role to play here in terms of age verification, and that's something that needs to be pursued with them and it's very much a part of our agenda here within the department."
Ms Foley commended the work of new media regulator, Coimisiún na Meán, which opened a public consultation on its draft Online Safety Code for video-sharing platform services in early December.
This will feed into a final document that will make digital services legally accountable for how they keep people safe online.
The draft code sets out measures that designated video-sharing platforms will be obliged to implement to keep their users, especially children, safe online.
These platforms will have to protect children from specific types of harmful content.
This includes cyberbullying; online content that promotes or encourages a feeding or eating disorder; and content that promotes or encourages self-harm or suicide.
The measures include using robust age verification technology to make sure that children are not exposed to inappropriate content, such as pornography.
Ms Foley said: "We just have to be very clear that young people in particular are accessing these opportunities in an age-appropriate manner.
"There needs to be an enforcement around age appropriateness.
"And there is the responsibility, particularly by the providers to ensure that that is happening."