Lucky skywatchers who spotted a rare daylight meteor streaking across the Victorian sky might never see one again in their lifetime, said one astronomer.

Reports of the burst of flame across the blue sky started flooding through on social media at about 10.30am on Wednesday, with one describing it as a "fireball asteroid".

Astronomical Society of Victoria spokesman Perry Vlahos said he had heard reports of the sighting across the state, from Mildura to Wangaratta to Melbourne.

"It appears to have come in from the western sky burning with a bright orange colour and leaving a white trail behind it," he said.

Mr Vlahos said the soaring fireball was probably a space rock that has been pulled in by the Earth's gravity and burned up in the atmosphere.