Australia has imposed a sweeping ban on social media for children under 16, one of the world’s most comprehensive measures aimed at safeguarding young people from potential hazards online. But many details were still unclear, such as how it will be enforced and what platforms will be covered.

After sailing through Parliament’s lower house on Wednesday, the bill passed the Senate on Thursday with bipartisan support. Prime Minister Anthony Albanese has said that it puts Australia at the vanguard of efforts to protect the mental health and well-being of children from detrimental effects of social media, such as online hate or bullying.

The law, he has said, puts the onus on social media platforms to take “reasonable steps” to prevent anyone under 16 from having an account. Corporations could be fined up to 49.5 million Australian dollars (about $32 million) for “systemic” failures to implement age requirements.

Neither underage users nor their parents will face punishment for violations. And whether children find ways to get past the restrictions is beside the point, Mr. Albanese said.

“We know some kids will find workarounds, but we’re sending a message to social media companies to clean up their act,” he said in a statement this month.

As with many countries’ regulations on alcohol or tobacco, the law will create a new category of “age-restricted social media platforms” accessible only to those 16 and older. How that digital carding will happen, though, is a tricky question.