Terrorism concerns prompted police to position a rooftop sniper to watch over Melbourne's Anzac Day dawn service for the first time.

The specialist officer was seen atop the Shrine of Remembrance yesterday and today Victoria Police Chief Commissioner Graham Ashton confirmed it's the first time a sniper has been assigned to the dawn service.

"It might be the first time at a dawn service but we have had those recent terror attacks overseas as well as here last year so we're not taking any chances and making sure we're well positioned," he told 3AW radio this morning.

A sniper on the roof as part of the security at the Shrine during the Anzac in Melbourne. (AAP)

The officer was clearly visible to the crowd of about 25,000 people, positioned behind the shrine's elevated granite bastion, looking through the sight of his rifle.

"Normally people don't see them but the way the shrine is set up, there's not a lot of high points around there, so a bit harder to conceal," Mr Ashton said.

"They are of course connected by radio to the other security presence and if there is someone there who we believe is going to be killing people then the snipers are empowered to act."

He added that the force only has a couple of snipers and it's "not unusual" to see them at big events.

"They are a regular feature of our security (operations)."