Adults with diabetes will now have greater access to Fiasp, a fast-acting mealtime insulin, thanks to its listing on the Pharmaceutical Benefits Scheme.

Adults with diabetes now have greater access to a rapid-acting insulin which can be taken just before eating a meal.

Fiasp, a new fast-acting mealtime insulin, has been subsidised by the government through a listing on the Pharmaceutical Benefits Scheme.

Senior endocrinologist at St Vincent's Hospital Melbourne David O'Neal says the medicine gives diabetes patients more flexibility and control.

"It allows them to be able to live their lives the way they want to and look after the diabetes rather than the diabetes controlling what they're doing," Professor O'Neal told AAP.

"It certainly eases the burden of the disease on the patient."

Diabetes affects about 1.7 million Australians, with a quarter of those patients needing to take insulin to manage blood sugar levels.

To manage blood sugar levels over the course of a day, some people may need to inject themselves several times.

Slower-acting insulins are taken about 15 to 20 minutes before a meal, whereas Fiasp can be taken just as someone with diabetes is about to eat.

It is available in a pre-filled insulin pen called FlexTouch.

"It comes onboard and then it goes away, and that's the advantage of that," Prof O'Neal said.

Patients say Fiasp has helped control their post-meal glucose levels, he added.

Prof O'Neal says the PBS listing will ensure patients have access to the medicine, particularly those who need it most.

"People should have access to medicines based on need, rather than what their resources are," he said.

While Fiasp is only for adults with diabetes, research is being done on a similar medicine for children and adolescents.