UPDATED 6:00pm: Five teenagers have been arrested over an alleged terror plot planned for Anzac Day in Melbourne.

Prime Minister Tony Abbott has urged his fellow-Australians not to be deterred by the alleged terror plot in Melbourne.

Teams executed a number of warrants in the city's southeast early this morning and say the men, aged 18 and 19, were planning to target police officers.

Acting Deputy Commissioner Neil Patton says people shouldn't feel scared.

"People in their community may feel anxiety today, they may be feeling alarmed. I would like to say that people shouldn't feel threatened as a result of this. What they should feel reassurance as a result of operations."

Mr Abbott urges Australians not stay away from Anzac Day events out of fear.

"People should turn up at Anzac day events in the largest possible numbers...the best thing you can do in the face of those who are doing us harm is live your life normally."