Vandals are behind the latest significant Optus outage, which cut emergency service calls for more than 14,000 people.

Wedneday’s issue was triggered by vandals who damaged an aerial fibre line, affecting users in the Frankston and Mornington Peninsula areas, south-east of Melbourne.

Optus spokeswoman Jane McNamara said crews were working to restore coverage, with five of the six affected sites back online before midday (AEDT).

Remaining customers were expected to be reconnected within hours.

McNamara said the incident was frustrating, adding that criminals had cut the fibre that provided vital connectivity to customers.

“Our technicians have been on site since early this morning. We do have that photo evidence and it’s clear that there had been a cut made,” she told ABC Radio Melbourne.

“We know copper has been removed from the pit and we have contacted police.”

The embattled telco’s website listed 14,322 services affected at midday.

“Optus customers will only be able to call emergency services if they are within coverage of another mobile network or are able to call via Wi-Fi,” the company’s website said.

Victorian Premier Jacinta Allan said she was seeking urgent advice on the situation.

“There are too many people out in the community experiencing an outage that may be impacting their ability to contact emergency services,” she said on Tuesday.

“I can understand why there is a great concern in the community, particularly given some of the more recent incidents that have involved Optus.”

It is the fourth time in months that a major Optus outage has prevented people accessing emergency services.

In September, a scheduled firewall upgrade in South Australia triggered a communications outage linked to the deaths of three Australians.

Optus chief executive Stephen Rue blamed human error for that fault.

Normal calls were largely unaffected but the outage blocked about 600 triple-zero calls from connecting to emergency services.

-AAP