SYDNEY, Nov 9 (Reuters) - A proposed Australian internet law could force Google to block under-18s from using its Gmail service, an Australia-based company ​policy head said on Monday, underscoring an industry warning that ‌the draft regulation risks overreach.

Under the Digital Duty of Care legislation, which has already passed Australia's House of Representatives but needs cross-party support to pass ​the Senate, internet companies must show they are taking steps ​to weed out harmful content or face a fine of ⁠up to A$109 million ($75.1 million).

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A section ​of the law requiring age checks if there was a ​risk of a child seeing pornography "could require us to age assure and block access ‌to ⁠everyday communication services like messaging, email and private file storage", said Rachel Lord, head of policy in Australia and New Zealand for Google's YouTube streaming website, at a Senate hearing.

"We are talking about ​potentially intrusive monitoring ​within private communications ⁠or file storage," she added.

Representatives from Meta, TikTok and Snap voiced similar concerns, warning the bill could ​chill online communications by allowing regulators broad discretion ​to determine ⁠what content or conduct is harmful while replacing some existing mandatory industry codes.

Several argued the uncertainty created a risk platforms would over-moderate content ⁠to ​avoid large regulatory penalties.

The government has said ​a broad set of rules is the only way to ensure a safe internet.

The ​hearing continues.

($1 = 1.4520 Australian dollars)

Reporting by Byron Kaye; Editing by Stephen Coates