Controversial former construction union boss John Setka allegedly threatened the union's administrator in a series of offensive and abusive emails.

The union heavyweight was arrested on Wednesday morning by state and federal police at his Footscray home, in Melbourne's inner west, where officers seized a phone and an iPad.

Police allege Setka sent threatening, offensive and abusive emails to CFMEU administrator Mark Irving following a production notice sent on October 27 and a follow-up letter sent the next day.

The 61-year-old has been charged with seven counts of using a communications device to menace, harass and offend.

He was bailed to appear at Melbourne Magistrates Court on January 30.

Setka quit after 12 years as head of the Construction, Forestry, Maritime and Energy Union in

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