Security will be ramped up on Anzac Day

Anzac Day will be accompanied by a strong police presence across Australia in the wake of Melbourne's terror raids, with Prime Minister Tony Abbott urging people to turn out in droves and show their support.

Victorian police launched pre-dawn raids in four Melbourne suburbs on Saturday, arresting five teenagers, two whom they allege were planning IS-inspired attacks on Anzac Day events.

Sevdet Besim, 18, from Hallam, has been remanded in custody after facing Melbourne Magistrate's Court charged with conspiring to commit terrorist acts.

An 18-year-old from Hampton Park is also expected to be charged with preparing for a terrorist act and remains in custody.

The three others have been released, with one expected to face charges on summons with weapons offences.

Following the arrests, Victorian Premier Daniel Andrews vowed to ramp up security and increase police numbers across Melbourne for Anzac Day events.

Mr Abbott echoed the sentiment, saying there would be a strong police presence across the country despite no specific threat in other cities.

"Please don't be deterred. Turn up in the largest possible numbers to support our country, our values and our armed forces," he told reporters.