Three men have been found guilty of engaging in a terror act by trying to burn down a suburban Melbourne mosque.

A Supreme Court jury today returned the verdict for Abdullah Chaarani, Ahmed Mohmed and Hatim Moukhaiber who had stood trial charged with crimes over the burning of the Imam Ali Islamic Centre at Fawkner on December 11, 2016.

The court was closed shortly after the verdict was returned as Moukhaiber said "you are dogs" to the jury and members of the public started calling out.

Mohamed and Moukhaiber had both denied any involvement and while Chaarani admitted he was there, argued he had been part of an act of protest, advocacy or dissent, and not terrorism.

Chaarani and Mohmed were also found guilty of attempting to commit a terrorist act over a failed first attempt to attack the mosque on November 25 the same year.