Britain in July is set to become the first country in the world to introduce age-verification to access online pornography, the government said on Wednesday.
Child protection groups welcomed the move but digital rights groups warned of the possibility of data leaks and the implications for online privacy.
The new law, which comes into force on July 15, will require commercial providers of internet pornography to check on users' ages to ensure that they are 18 or over.
Different sites will use different verification methods ranging from online passport or credit card checks to special vouchers that can be bought in shops.
"Adult content is currently far too easy for children to access online," Minister for Digital Margot James said in a statement.
Websites that fail to implement the verification technology could have payment services withdrawn or be blocked for British users, according to the Department for Culture, Media and Sport (DCMS).
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It is the latest move by British authorities to crack down on the spread of online abuses and crimes.
The government announced earlier this month proposals to make social media bosses personally liable for harmful content and shut down offending platforms.
The latest step to bring in age-verification for pornography follows public consultation and parliamentary debate on the issue last year.
Research conducted as part of that outreach found that 88 percent of parents with children aged seven to 17 supported new controls, DCMS said.
The department insisted the range of checks to be carried out by providers would be "rigorous" and go beyond users simply entering their date of birth or ticking a box.
The British Board of Film Classification (BBFC) will be responsible for ensuring compliance.
The government said it had "listened carefully" to privacy concerns and was clear the arrangements should only be concerned with verifying age -- not identity.
The BBFC will therefore also create -- in cooperation with industry -- a voluntary certification scheme to assess the data security standards of the providers.
Internet Matters, a non-profit organisation concerned with online child safety, said it was "delighted" that the government tackling the issue but also sounded a cautionary note.
"We must recognise that digital solutions aren't the only answer," said its CEO Carolyn Bunting.
"There is no substitute to having regular and honest conversations with your child about what they're getting up to online."