OPINION: The debate over allegations of misbehaviour by our federal politicians has an important subtext. Does Australia have the right laws and institutions in place to deal with accusations of corruption, including misuse of travel entitlements and electoral fraud?

Unfortunately, we do not. The lack of a national anti-corruption body means that dishonesty and breaches of public trust by parliamentarians and Commonwealth agencies may never be detected, let alone addressed.

Improving the accountability of our politicians has focused on the idea of a new code of conduct. Such codes usually amount to grand statements about how politicians ought to behave. They are generally unenforceable, except through the actions of other politicians.

Although there is no harm in having a code of conduct for the federal Parliament, it is likely to be ineffective.

The federal opposition has understandably been critical of a new code of conduct. What has been surprising is that they have not taken the lead in arguing for stronger mechanisms to oversee the work of parliamentarians and public servants. The running on this has instead been left to the Greens, who late last week reinvigorated their 2010 bill in the federal Parliament to establish Australia's first national anti-corruption body.

The Greens' bill would create a national integrity commissioner responsible for preventing and fighting corruption by parliamentarians and in federal agencies. At present, such anti-corruption powers are held nationally by the Australian Commission for Law Enforcement Integrity, which can examine only bodies such as the Australian Federal Police.

The case for whole of government anti-corruption bodies has proved overwhelming in the states. They are now in place, or being established in every state jurisdiction.

The first state body was the NSW Independent Commission Against Corruption, established in 1988. It is a key part of the political landscape and has a formidable record of investigating and exposing corrupt conduct. Its very public pursuit of corruption can itself be a significant deterrent.

There is no rational reason why a strong anti-corruption body is needed at the state level and not for the Commonwealth. State bodies cannot investigate corruption by federal parliamentarians and officials but dishonesty and misuse of public power are not limited to state and local governments.

Australia has a generally good record of avoiding corruption at the federal level. However, there are still many examples, including the AWB wheat for oil scandal, corruption allegations levied against an offshoot of the Reserve Bank and all too regular instances of politicians misusing their travel or other entitlements.

The potential for corruption is always present because of flaws in how federal elections are funded. Politicians must raise tens of millions of dollars for each poll and in doing so face the temptation to receive funds in return for favourable decisions. This problem has been known for decades, with a 1989 joint standing committee report entitled Who Pays the Piper, Calls the Tune finding that fund-raising practices ''create the potential'' for corruption.

Corruption can be tackled only under an ad hoc collection of federal laws. For example, the police can investigate allegations of bribery and the Australian Electoral Commission can examine failures to disclose political donations. Other breaches of public trust and dishonesty can fall between the cracks. It can be unclear which agency is responsible for a matter or indeed, in the absence of a broad federal definition of corruption, whether an allegation can be investigated at all.

This can lead to failures to prevent corruption and an under-reporting and under-investigation of the problem. In NSW, anyone with a lead on corrupt conduct can go to the ICAC website, where a prominent ''report corruption here'' button invites them to take action.

At the federal level, people with information can find it hard to know where to start, which may stop them from coming forward.

If the scandals that have engulfed our federal politicians are to lead to any good, they may finally help to bring about changes to federal anti-corruption law. Certainly, something must be done to restore public confidence in our politicians and institutions. A national anti-corruption body would be a good place to start.

George Williams is a Professor of Law at UNSW. 

This opinion piece first appeared in The Sydney Morning Herald