Older Australians are failing to vaccinate against a common and often fatal type of pneumonia, experts warn.

Older Australians and people with chronic health conditions are doing little to protect themselves from an often fatal lung infection.

The Lung Foundation of Australia says vaccination rates for pneumococcal pneumonia are alarmingly low, despite it being responsible for a large proportion of pneumonia cases among those aged 65 and over.

The vaccine is free for Australians aged 65 and over and can also be free for some people with chronic health conditions.

The foundation hopes more people will protect themselves against the infection if they understand it won't cost them anything.

"This is a really safe vaccine and it's an important one for GPs to talk to their patients about," infectious diseases physician William Rawlinson has told AAP.

"We know from research that patients take a lot of notice about what their doctors recommend."

Prof Rawlinson said about 77,000 Australians were hospitalised each year with various types of pneumonia, and about half of those cases involved people aged over 65.

He said he hoped people would act when they realised vaccines were available for the most common types of pneumonia, including pneumococcal pneumonia.