FAWNA says the decision to remove its ability to remotely divert its 24-hour emergency phone number between volunteer phone operators is affecting its ability to efficiently receive calls.

The rescue service's president Meredith Ryan described the situation as "a nightmare".

“No longer having the communications technology to be able to quickly and efficiently service the needs of the district’s wildlife in need is the worst part," Mrs Ryan said.

But Telstra says it advised FAWNA via their last bill notices that from September the telecommunications giant would start retiring a number of PSTN (the traditional analogue phone system) features.

This included the call forwarding feature that FAWNA was utilising. It says that information is also available on its website.

“We understand that change can cause concerns and we have attempted to advise customers of these changes via their bills and on our website," a Telstra spokesperson said.

"The use of these PSTN features by our consumer customers is low and has been steadily declining over the years as technology changes the way we communicate."

It is understood that the use of PSTN features is low across the Telstra network and has been in decline for some time as technology changes the way we communicate.

Phone users are now more likely to opt into mobile phones and smart messaging apps.   

The remote diversion feature FAWNA formerly used is available for business customers.

Mrs Ryan said the volunteer service was totally reliant on an efficient phone service.

In the last financial year the service received and made some 220 phone calls through the emergency number.

"And September is our peak time too," she added.