On Wednesday, Optus chief executive Kelly Bayer Rosmarin said it was too “technical” to explain what happened, but the company would offer a full explanation once it got to the root cause of the issue.

In a statement on Thursday, Optus said: “In common with major global telecommunication networks, the Optus network is designed with multiple layers of fallback and redundancy.

The key piece of equipment that might have brought down Optus comes via ChinaTechNews.com.