Eden Monaro byelection: AFP charge laid over 'offensive' spam emails targeting Labor's McBain

The Blacktown man was arrested during a search warrant at his house on Thursday night and later charged with one count of using a telecommunications service to menace, harass or cause offence.

Emails have been sent during the campaign falsely claiming Ms McBain had pulled out of the race and votes wouldn't be valid unless they preferenced Liberal candidate Fiona Kotvojs above Labor.

Other emails have claimed to be from the Catholic Church and accused Ms McBain of being involved in the prosecution of Cardinal George Pell and the coronavirus pandemic.

The AFP has not confirmed which emails were involved in the arrest and charges.

Ms McBain said she welcomed the arrest and thanked the AFP for their work.

"It's obviously concerning that [the email campaign] potentially has an impact on [Saturday's vote]," she said.

"I think any misinformation campaigns like we have seen with the email trail have been disappointing and is not something we want to see in our democracy."

Dr Kotvojs has previously condemned the emails.

An AFP statement said it began an investigation following a report from the Electoral Integrity Assurance Taskforce and the Australian Electoral Commission on June 10.

"The report related to spam emails, which appeared to be from legitimate sources, being sent from an unidentified user to the Australian community and various organisations," the statement said.

"The emails were assessed as offensive and harassing in nature,

"The AFP investigation identified the use of a number of telecommunications services subscribed using suspected fraudulent identification documents. Investigators will allege in court that these activities were linked to the 32-year-old man."

The man was released on police bail and is due to appear before the Blacktown Local Court on September 2.

Dr Kotvojs has previously condemned the emails.

The AFP said an investigation into the matter remained ongoing.

The Australian Electoral Commission said it was aware of the AFP's action in relation to " a series of spam emails circulated regarding the Eden-Monaro byelection".

"The AEC takes this matter, and all electoral integrity matters, very seriously," the commission's statement said.

"The AEC initially referred the matter to the Electoral Integrity Assurance Taskforce for consideration on June 10 and has continued to provide evidence to support the investigation."