The union representing postal workers has described as "harebrained" the prospect of residents across Australia being charged a fee to receive daily mail.
Australia Post recently conducted a survey asking customers if they would prefer to have their mail deliveries three times a week or pay an annual $30 fee for daily delivery, News Corp Australia reported on Tuesday.
But Australia Post denies it's planning to scale back daily door-to-door deliveries, according to the report.
On Tuesday, the Communications Electrical Plumbing Union (CEPU) said Australia Post "should be ashamed for raising the prospect of charging residents for their daily mail".
"Australia Post is a profitable operation and it should not be raising ideas like charging recipients for mail services which have already been paid for through postage, NSW CEPU postal and telecommunications secretary, Jim Metcher, said in a statement.
"Floating these sorts of harebrained ideas only talks down the future of the postal service."
He said making people pay for daily delivery would mean "fewer and fewer people use the service, leading to post office closures and loss of confidence in Australia Post".
"Posties carry both parcels and letters of all shapes and sizes on their delivery rounds each day, they are complementary services," Mr Metcher added.
The reported survey by Australia Post comes after the company lost a record $187 million on its traditional mail business last year.
Australia Post said the survey was "in no way an indication of what may or may not be implemented in the future.
"Every year we ask customers about service preference through surveys," the company said in a statement.
"We remain focused on our community service obligations, which we have met."
However, it recognised customer needs were changing.
"We continue to grow our services to meet the changing preferences of our customers," the company added.