Federal politicians caught up in the dual citizenship saga have been dubbed "wilfully blind" by lawyers for two former Greens senators who resigned from parliament over their own foreign ties.
Six of the seven politicians under a citizenship cloud, lodged their legal arguments with the High Court on Thursday, which will decide whether they should be booted out.
One Nation senator Malcolm Roberts is yet to submit his paperwork.
Lawyers for former Greens senators Larissa Waters and Scott Ludlam argued their resignations were the correct course of action.
"Ignorance or wilful blindness ought not excuse a person from the constraints of the constitution that would disqualify a more diligent or more perceptive candidate," the submission says.
"The referrals presently before the court fall into the category of ignorance or wilful blindness."
Under section 44 of the constitution, "a subject or a citizen ... of a foreign power" cannot stand for parliament.
Deputy prime minister Barnaby Joyce's submissions states that from the age of 10 he believed his father was solely an Australian citizen.
James Joyce migrated to Australia in 1947 and became an Australian citizen in 1978.
"Mere knowledge that his father had been born in New Zealand can not be said to have constituted knowledge of circumstances that ought reasonably to have put Mr Joyce on inquiry as the possibility that he might have been a New Zealand citizen," the submission states.
Mr Joyce, who has remained in cabinet, has only ever travelled to New Zealand once to attend his grandmother's funeral as a child. He's renounced citizenship of NZ.
The submission of deputy Nationals leader Fiona Nash, who has also remained on the frontbench, reveals her father was born in Scotland and her older sisters were born and lived in England before the family moved to Australia in the early 1960s.
It contended she was estranged from her father following her parents' divorce and had not travelled to Britain. She has since renounced citizenship of Britain.
Lawyers for former resources minister Matt Canavan, who stood aside from the ministry over the saga, argued the way he was granted Italian citizenship - retrospectively, and without his knowledge - may have violated Italy's constitution.
His submission says his mother registered herself for citizenship and listed him as one of her children. He has officially renounced his Italian citizenship.
Crossbench senator Nick Xenophon's legal team questioned why the "slenderness" of his British citizenship should cost him his seat.
He's learned he is a British overseas citizen by descent, as his father was born in Cyprus when it was still a colony.
Senator Xenophon's legal team emphasised he had suspected he might have had citizenship of Cyprus or Greece and had looked into making renouncements but this was not the case after all.
The matters will go before the full bench of the High Court on October 10.
