Part of the requirements of becoming a federal politician is making a declaration to the AEC. There is one question that is asked of all candidates. It asks if you are compliant with s44(i-v) of the Australian Constitution. A seemingly innocuous question on a bureaucratic form. The link below is a sample copy of a HOR candidates form. The Senate version is very similar. http://www.aec.gov.au/Elections/candidates/files/60-60b-single-regofficer-sample.pdf
The point of the law is to ensure all political candidates are loyal to this nation. That they are not compromised by their investments when making legislation. That they are honest. Apart from gathering signatures of eligible voters and the fee, it costs to run for parliament s44(i-v) is the only thing asked of a candidate. Many people get angry about s44(i) as it prohibits dual citizens from running for parliament. People who advocate for compliance are often referred to as birthers. They think that the law is racially motivated. In actual fact this argument is ludicrous. It is very possible for an Australian born person to become a dual citizen. The legal requirement is to ensure allegiance to The Commonwealth Of Australia.
The recent events in Canberra with MPs & Senators being questioned, resignations & at least one matter being referred to the High Court have happened because this law has never been audited. While it has a serious warning after it on the nomination forms. There is no enforcement. A breach of s44(i-v) Constitution does mean that the candidate is ineligible to be in Parliament. Knowingly making a false declaration is a breach of the Criminal Code Act 1995. It carries a maximum punishment of 12 months jail. Of course, once one matter goes unpoliced the fear of penalty diminishes for all who follow.