White supremacist Jacob Hersant has become the first person found guilty of breaking a Victorian law that bans performing the Nazi salute in public.

Warning: This story contains language and details some readers will find distressing.

Hersant was outside the County Court last year, having just been sentenced for another offence, when he raised his arm and made a salute in front of journalists.

He quickly lowered his arm and said: "Oh, nearly did it, it's illegal now isn't it?"

As he walked away, Hersant called out: "Australia for the white man, heil Hitler."

Hersant performed the gesture days after Victorian lawmakers passed the Nazi Salute Prohibition Bill, making it illegal to deliberately perform the action in public.

The offence carries a maximum penalty of $23,000 or 12 months' jail.

On Tuesday, Magistrate Brett Sonnet ruled Hersant was guilty of performing the salute, after the neo-Nazi fought the charge and argued the laws were constitutionally invalid.

Magistrate Sonnet said Hersant knowingly performed the salute, which he described as "an inherently political act" intertwined with Nazi ideology.

The magistrate said laws were necessary to protect vulnerable minority communities.

In a summary read out to the court, the magistrate said he rejected arguments from Hersant's lawyers that the laws were in breach of the constitution.

The magistrate said his full decision, which could be published online this week, stretched to 184 pages.

Hersant will return to court tomorrow for a pre-sentence hearing.

Hersant, who was supported in court by his mother, showed no visible reaction when the decision was announced.

Outside court, he said he was considering his appeal options, and proudly declared that he continued to hold Nazi views and was not worried if he was sent to prison.

Victorian Premier Jacinta Allan said Hersant's conviction sent a clear message that anti-Semitism would not be tolerated.

"We took very, very strong action as a government, as a parliament, as a society, to say that … Nazi salute behaviour is utterly unacceptable," Ms Allan said.

"It should be prosecuted, it has been."

Dvir Abramovich, a Jewish activist and chairman of the Anti-Defamation Commission, called the decision "a historic and thundering day for justice and decency".

"I am moved beyond words and filled with a profound sense of relief," Dr Abramovich said.

"This decision means that no one in this state should have to live in fear of seeing this expression of absolute inhumanity and terror in the places they call home."