Richard Marles, also Australia's defence minister, has highlighted the "historically unprecedented" attacks on critical infrastructure on the ocean floor.
"It is striking that several cables have been severed across the Baltic and the Taiwan Strait since November 2024," he said at 2026 Shangri-La Dialogue, without levelling accusations at individual countries.
"Now, maybe these were accidents," he added at the Singapore defence meeting on Saturday.
"But even if they were, it highlights the vulnerability of this crucial part of the globe's infrastructure."
With roughly 99 per cent of Australia's internet flowing through just 15 subsea cables, Mr Marles said Australia was among the most exposed nations in the world to this "documented pattern of behaviour".
Pacific island nations were even more vulnerable as they were often served by a single cable.
"These cables are, in the most literal sense, the arteries of modern civilisation," he said.
"Our financial systems, our health systems, our communications, our intelligence partnerships, our ability to operate as a modern economy and a functioning state: all of it is critically dependent on infrastructure that is exposed, that cannot move and - as we have now seen demonstrated in the Baltic - can be cut with an anchor in the middle of the night."
Australia's dependence on subsea cables has been identified as an "Achilles' heel" by the Australian Strategic Policy Institute, with cables converging at a few landing points and many following similar routes, leaving them vulnerable to attacks on multiple lines at once.
Australia's growing reliance on artificial intelligence tools and corresponding demand for high-speed, reliable internet connectively is leaving the nation even more vulnerable to subsea cable disruptions.
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