Singtel-owned Optus was hit by another outage of its emergency call system yesterday (28 September) in Australia’s New South Wales region, with the company investigating the cause of an issue involving a mobile tower site.

In a statement, the operator explained the issue lasted about nine hours and impacted a population of about 4,500.

Optus noted it restored the site and all services, and issued an apology to customers impacted. The company added “where necessary” it is working with the police as part of the emergence call welfare check process.

Singtel, in a separate release, noted the incident is unrelated to last week’s outage, adding it was a different type of outage, which was limited to one cell site out of 3,140 in New South Wales. “This incident did not arise from any upgrade or maintenance action being conducted.”

It confirmed one person requiring emergency services was impacted, but the person was able to call emergency services from another phone successfully.

Optus suffered a 13-hour disruption to its emergency call system on 18 September, which led to multiple deaths. The outage occurred during a routine firewall upgrade.

Optus started an independent review of the outage to determine what went wrong.