Text messages between Auburn's former deputy mayor Salim Mehajer and his sister prove they plotted to rig the Auburn Council election in 2012, prosecutors tell a Sydney court.

Mr Mehajer and his sister Fatima Mehajer are accused of lodging false documents with the Australian Electoral Commission (AEC).

The siblings face at least 70 charges each, with federal police alleging they fabricated addresses on AEC enrolment forms to increase Mr Mehajer's chance of becoming a councillor.

Mr Mehajer and his sister were not required to attend the Downing Centre Court today for pre-trial argument, and they were not there.

Prosecutor Michelle England told the court the crown had evidence to prove the accused knew what they were doing when they lodged more than 70 false documents with the AEC on July 30, 2012.

She said on the same day, the siblings sent texts to each other discussing the false addresses.

The court heard Ms Mehajer wrote a message to her brother that read: "no such address. I'll re-enrol him".

Mr Mehajer's reply, according to the prosecutor, read: "lol it's just Greenacre, waters makes it sound fancy".

'Make sure they are all in AUB'

Ms England said Mr Mehajer instructed his sister to fill out the enrolment forms for the candidates in his group.

"Who is in my group? What are their addresses? Make sure they are all AUB," a text from Mr Mehajer read.

"The words 'make sure they are all in AUB', meaning Auburn, were repeated 11 times in texts Samil Mehajer sent within five minutes," the prosecutor said.

The court heard the documents were lodged from two internet provider addresses; one belonging to Mr Mehajer's Lidcombe house, the other his business at Sefton.

Defence lawyer Hament Dhanji SC rejected the crown's evidence as "defective".

"The objective is not to get people with false enrolment details to support them, but simply to support them," he said.

"The desire is not illicit here; the desire is to have people vote for them.

"Indeed, one might think there'd be a preference that the ones that were voting for them were people in the actual electorate."

The trial is set to start in June.