Australia's oldest person has celebrated her 112th birthday in Melbourne today.

Emily Beatrice 'Bea' Riley was born in 1896 in the Gippsland dairy town of Poowong.

She will mark her birthday with a small gathering at her Rosanna nursing home later today.

Mrs Riley has seen two appearances of Halley's Comet, the Federation of Australia, and watched man land on the moon.

She is listed as the 30th oldest person in the world.

She is also part of a select group known as supercentarian, a person who reaches 110.

Another Victorian woman turns 112 in December but Mrs Riley is the oldest documented person.

Australians now have the world's second-longest life expectancy after Japan.