* Inquiry examines amendments to double maximum penalties to

A$99 million

* Meta says it deactivates 756,000 suspected underage

Instagram and Facebook accounts, up from about 500,000 in March

* TikTok says it removed 550,000 accounts when law took

effect and about 24,000 monthly since

By Byron Kaye

SYDNEY, Aug 14 (Reuters) - Top social media platforms urged

the Australian government not to place too much weight on early

evidence showing most children still use their products despite

a landmark under-16 ban, as lawmakers weigh tougher penalties

and investigative powers for regulators.

Local heads of YouTube owner Google, Facebook and

Instagram owner Meta, Snapchat and TikTok

fronted a Senate inquiry as lawmakers pressed them on multiple

studies, including from Australia's internet regulator, showing

some 80% of minors were still on social media months after the

ban took effect in December.

The hearing showed a persisting divide between lawmakers and

big tech over whether the ban is working at a time when the

eSafety Commissioner is considering legal action against some

platforms, accusing them of deliberately slow-walking compliance

to discourage other jurisdictions from copying it.

The inquiry is examining amendments that would double

maximum penalties to A$99 million ($64 million) and expand the

commissioner's powers to compel information and documents from

platforms and their third-party age assurance providers during

investigations.

"It is a point in time, it's very early on, and we caution

against over-reliance on that," YouTube's head of government

relations Rachel Lord told the inquiry, noting the government's

latest published compliance data was from March.

Age assurance technology had largely been built around a

cut-off of 18, which many jurisdictions consider the transition

from childhood to adulthood, and "the technologies that we are

using to detect users at the 16 age boundary are evolving", Lord

added.

Meta's Australia head of public policy Mia Garlick said the

data on which the research was based may not reflect whether

underage users had an account, even if they claimed to use a

platform.

"There can be differences in terms of people accessing

versus having an account," she told the inquiry.

"Sometimes survey data is challenging in terms of stated

versus revealed."

Meta released figures a day earlier showing it had deactivated

756,000 Instagram and Facebook accounts suspected of belonging

to underage users, up from about 500,000 in March. YouTube's

Lord said Google has stopped about 740,000 holders of Google

accounts from using their accounts to use YouTube.

TikTok's Australian head of public policy Jessica Loftstedt

said the company's compliance efforts were an "iterative

process". The company had taken down 550,000 accounts when the

law took effect and had since been removing about 24,000 a

month.

The eSafety commissioner is scheduled to testify at the

inquiry later on Friday.