Ms Wertheim has been charged with contravening an intervention order, four counts of unlawful assault, recklessly and intentionally causing injury and resisting police.
After her arrest on Monday night, she was placed under police guard in a Melbourne hospital.
She is due to face Melbourne Magistrates Court on October 27.
Ms Wertheim, who allegedly has a history of pestering ALP staffers, is accused of pushing and grabbing Ms Garrett by the hair in a “frightening” attack, outside the Shaw Davey Slum Pub on Elgin Street.
Ms Garrett said the assault had “completely shattered” her sense of peace and left her feeling sore around the neck and back.
“It was in broad daylight, it was just a shocking incident,” Ms Garrett told reporters on Tuesday morning.
Ms Wertheim is the ex-girlfriend of former Hunters & Collectors frontman Mark Seymour, who in 2006 was granted an intervention order against her.
In a chilling court statement Seymour said: “I am just plain and simply scared of her.”
Back then, the court heard Ms Wertheim had sent more than 20 emails to Seymour’s manager and colleagues between November 2004 and February 2006, had been to his home and had verbally abused him from behind a fence at a concert in 2006.
She also left a message on his elderly parents’ answering machine.
In June 2006, Magistrate Kate Hawkins told Ms Wertheim that she had embarked on a campaign of harassment against Seymour, who she was in a 4-year relationship with until 1992.
“[The harassment] was designed to cause him [Seymour] emotional harm and distress and also a loss of work opportunities,” Ms Hawkins told the court after granting an intervention order.
In a tweet on Tuesday morning, Ms Garrett thanked friends and family for their support.
It is believed Ms Garrett knew Ms Wertheim, and had taken out an intervention order against her in the past.
Another politician told Fairfax Media that Ms Wertheim pushed her and yelled at her at a voting booth during an election in recent years. The confrontation followed continued harassment directed at her workplace.
“She targeted our phone lines,” the politician, who preferred to remain unnamed, said.
Premier Daniel Andrews said what happened to Ms Garrett was a “shocking incident”.
“It just reminds us that some in public life will encounter these sorts of nasty incidents from time to time, we all have to be vigilant,” Mr Andrews said.
But he said Australian MPs were generally pretty lucky to be able to move freely in their community.
“This was a shocking incident, an isolated one thankfully, our thoughts are with Jane and we hope she is OK,” the Premier said.
Once seen as a rising star in the Labor government, Ms Garrett resigned as emergency services minister in June after refusing to back Mr Andrews’ revised workplace deal for paid CFA firefighters. Monday’s incident was not linked to the CFA dispute, or the United Firefighters Union.