But Setka appeared unfazed as he left Melbourne Magistrates Court on Wednesday, telling reporters he was "happy" about the threats.
The former head of the Victorian branch of the CFMEU is accused of sending his own threatening, offensive and abusive emails to the union's then-administrator Mark Irving.
Police allege Setka sent the emails in October after receiving a production notice and then a follow-up letter.
He has been charged with seven counts of using a communication device to menace, harass and offend.
Setka's lawyer on Wednesday sought an adjournment, telling the court he had requested material from Victoria Police and the CFMEU but was still awaiting disclosure.
Prosecutor Alex Turner said police would be objecting to the release of at least four documents, citing issues around relevance.
Another two documents sought from the police were not actually in their possession and instead needed to be requested from the CFMEU, Mr Turner said.
Magistrate William Parker adjourned the case off to a special mention hearing in September where a contest over the documents will be heard.
When the magistrate then raised applications from the media to access documents, Setka's lawyer told the court his client had been subjected to threats to kill.
The police were still investigating the threats, the lawyer said as he sought for Setka's address to be redacted from the released charge sheets.
Outside court, Setka was asked by reporters how he felt about the threats.
"Happy," he answered before continuing to walk away.
Setka was head of the Construction, Forestry, Maritime and Energy Union in Victoria for 12 years but he stepped down in 2024 following a Nine investigation into criminal links within the construction industry.
The reporting alleged major Victorian and NSW construction projects had been infiltrated by underworld figures and bikies acting as union delegates.
Setka said the allegations against the union were false but said he would step down to stop the barrage of stories.
He is separately facing legal action by the Fair Work Ombudsman over allegations he tried to coerce the AFL into sacking its chief umpire.
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