SYDNEY (Reuters) -Software owned by Australia's biggest banks is being tested as a way to comply with a teen social media ban, which begins in December, people involved in the process said, potentially involving the country's financial sector in the world-first regulatory crackdown.

    ConnectID is an identity verification tool owned by Australia's top lenders, which confirms a person's age from their bank account details. It is part of a package of software being pitched by Singapore-based age estimation provider k-ID, which uses facial estimation technology to pick a user's age.

    The pairing is already being tested by some social media companies in Australia, said k-ID, although it declined to say which. k-ID supplies age estimation for chatroom-focused platform Discord in Britain, which recently rolled out a lower-age restriction for adult content.

    ConnectID confirmed the partnership with k-ID, adding that no clients had signed up yet for help with the social media ban.

The companies also want to sell their partnership to gaming platforms in Australia, which are not affected by the social media ban but face separate laws forcing tighter content moderation for younger users.

The tie-up could mean an unexpectedly central role for Australia's banking sector in the rollout of a law that is being closely watched around the world as jurisdictions move to protect teenagers online.

ConnectID was one of dozens of age-assurance providers in a government-commissioned trial of the technology this year, but its partnership with k-ID and the fact that it is being tested by social media firms has not been reported before.

The Australian company links a website to a user's bank account, which sends an anonymous signal confirming whether they are over a specified age. Most teenagers have a bank account, so could use ConnectID for an accurate reading if a facial estimation tool gets it wrong, the company said.

"It's something we've been doing with major partners over the last couple of years across any ID," said ConnectID managing director Andrew Black in an interview.

"Age assurance and social media is an interesting inflection point for that."

The trial found age-guessing software generally could enforce the ban, but that the accuracy of selfie-based age estimation systems dipped around the cut-off of 16 years of age, according to a report published last month.

The government has said social media firms should offer progressively more accurate options for users to confirm their age.