Emma Walters, 46, has been charged with incitement to commit conspiracy to murder Sekta, the Victorian secretary of the Construction, Forestry, Mining and Energy Union.
Police have alleged Walters attempted to acquire a firearm and made threats to kill him last month, with investigators searching her Footscray home and seizing a mobile phone.
She faced Melbourne Magistrates Court by video link on Wednesday.
Prosecutor Laura Zubreckyj asked the magistrate to attach conditions to her bail about who she can contact, banning her from speaking to private investigator Adrian Peeters.
She also cannot contact any past or present employees of Group One Investigations, nor prosecution witnesses.
Walters, who has denied all allegations, reportedly spoke to a security expert about her situation.
Setka and Walters have been involved in a long-running legal battle involving allegations he committed acts of domestic violence, which he has denied.
She is also suing the Victorian government over claims police failed to protect her.
Her bail was extended and Walters will next face court on July 17 for a committal mention.
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