SYDNEY (Reuters) -Australian telco Optus said on Wednesday it had suffered an emergency call outage near Melbourne impacting around 14,000 users, two months after a broader disruption that probably caused four deaths when customers failed to get timely aid.

Optus, owned by Singapore Telecommunications, said an "aerial fibre break" could be the cause of the outage, which was being investigated.

"Customers will only be able to call emergency services if they are within coverage of another mobile network or are able to call via WiFi," the company said on its website.