The removal of Australian citizenship, even from dual nationals, would have to be subject to an appeal process. If it involved a court of law to underline the objectivity of the decision to the Muslim population, a general government assertion of removal being in the national security interest is unlikely to impress a court without substantial evidence of that being the case.

This could mean a requirement for the court to be security-cleared for access to security-classified material. We already know from the Lappas espionage case that this is a complex, expensive and protracted process because, if the information is highly classified and foreign-sourced, it could take 12 months or more to obtain the necessary approval.

Suspension of citizenship for a sole citizen outside Australia is sailing close to the wind if that effectively makes them stateless. Indeed, Australia could be in breach of the 1961 Convention on the Reduction of Statelessness – a UN multilateral treaty that Australia ratified under which sovereign states agree to reduce statelessness.

Australia could however suspend citizenship – as the UK has done – within Australia. It could also temporarily suspend the right of a citizen to return to Australia.

There are ongoing arguments about the pros and cons of dual citizenship. On the pro side, Australians are inveterate travellers and having two passports gives more flexibility with overseas travel, work, residency and inheritance. Millions of Australians either have two countries' passports or are entitled to them. On the con side, some dual passport holders use one passport to leave Australia and the other to obscure their onward travel for both criminal and terrorism-related reasons.

Not many Australians will remember that until 4 April 2002, Australians who gained another citizenship automatically lost their Australian citizenship. This changed because it was believed that trade and multicultural advantages flowed from Australians having dual citizenship. It was also hard for the government to know who had dual citizenship. Finally, it created an anomalous situation where immigrants could have dual citizenship while true-blue Australians couldn't.

The government also found it difficult to deny Australians who had lost or given up their citizenship from regaining it. In 1998 fraudster Christopher Skase took out Dominican citizenship with his wife Pixie to avoid extradition back to Australia and they automatically lost their Australian citizenships. In 2004, Pixie wanted to return to Australia and applied for an Australian passport. The government of the day refused to give her one. She appealed through the Administrative Appeals Tribunal and got her passport back.

Some Australians are still not permitted to have dual citizenship on the questionable ground of divided loyalties. For example, you cannot be a member of the Senate or the House of Reps as a dual citizen. On the other hand, many of our dual citizens hold top-secret security clearances.

Some countries still do not allow their citizens to hold dual or multiple citizenships. In some cases the loss of citizenship is automatic when another citizenship is gained. This is true of Austria, Azerbaijan, China, Denmark, India, Indonesia, Japan, Kazakhstan, Nepal, the Netherlands (under certain circumstances), Norway and Saudi Arabia (if obtained without permission).

A strong argument for allowing Australians to continue to hold dual citizenship is that it could allow the government to revoke Australian citizenship without leaving the person stateless.

Australian citizens by birth cannot currently have their Australian citizenship revoked. Similarly, those conferred with citizenship after fully disclosing all relevant factors cannot have their Australian citizenship revoked.

Under existing legislation, Australian citizenship can be revoked if it is deemed "contrary to the public interest for the person to remain an Australian citizen". Such a general ground would seem difficult to enforce. Legislative reform would be needed to make it easier to remove citizenship on national security grounds. The UK, France and Canada already have legislation to strip citizenship from dual nationals considered to pose a national security threat.

Once dual nationals have had their Australian citizenship revoked and any appeal grounds considered they could be forcibly deported from Australia provided that did not place them at risk – in which case they would have to go into indefinite immigration detention or go somewhere that would accept them.

Looking at the case of our Islamic State foreign fighters, it seems likely that many would have become Australians by birth as second-generation migrants. Many are probably also dual nationals by dint of their parents' country of origin. It would also be worth checking the background of any foreign fighter who gained dual Australian citizenship by application to see if there are reasonable grounds for citizenship cancellation.

Another option for the government is extending the cancellation of passports on security advice.

On February 10, Foreign Minister Julie Bishop said that to date, the passports of 90 Australians had been cancelled and five suspended. A further 10 passports were not issued. Under the Australian Passport Act 2005, passports can be refused or cancelled by the Foreign Minister on advice from ASIO or the Australian Federal Police – which can be on national security grounds.

The government could also cancel the passports of Australians who are in proscribed areas without good reasons for being there, and effectively prevent them from returning by putting their names on a travel watch list. This would probably require amendment of the Australian Passport Act.

Those affected could challenge this action, but it would take time and effort and would be one way of shedding ourselves of undesirables, possibly for several years. The government could also limit access to Australian appeal processes for anyone resident outside Australia.

Clive Williams is an adjunct professor at Macquarie University's Centre for Policing, Intelligence and Counter Terrorism and a visiting professor at the ANU's Centre for Military and Security Law.