One Nation Senator Malcolm Roberts has insisted his case is stronger than other federal MPs caught up in the dual citizenship debacle.

In a submission to the High Court published on Friday, Senator Roberts argued his case was different to others facing the court because while he had a subjective belief he was only Australian, he alone "sensibly appreciated the possibility he might be wrong".

One Nation senator Malcolm Roberts leaves court in Brisbane last week. Credit:Regi Varghese

"The fundamental fact remains he did not know or believe he was anything other than Australian," his submission argues.

Section 44 of the constitution prohibits dual citizens from serving in the Parliament.