Victorian police say they hold grave fears for the safety of a young girl at the centre of an extraordinary national appeal for information.

Police are worried about the safety of a young girl pictured inside what could be an Australian apartment in May last year.

Victoria Police say at the time the images were taken the Caucasian girl was between four and six years of age with shoulder-length brown hair.

"Other factors known to police are that the girl appears to be in an apartment or similar which is well furnished, with modern, large windows and is possibly overlooking a city skyline or other tall structures," police said in a statement on Tuesday.

"An AFL game is being played 'live' on a television in the background so it is thought the girl is within Australia."

In appealing for public help the police released images of the girl but wouldn't say if they were photographs or stills taken from a video.

News break – March 8