FORMER Australian military personnel are among thousands of private security guards who have been hired to protect commercial shipping in the Indian Ocean against attacks by Somali pirates.
In a growing free-for-all on the high seas, merchant shipping operators are turning to what are effectively private navies to safeguard their vessels and cargoes.
A Lowy Institute military analyst, James Brown, says as many as 2700 armed guards are operating aboard merchant ships plying the Indian Ocean trade routes.
Most are British or American but ''contractors from Australia and New Zealand are common too because their military training is interoperable with the US and UK'', he says.
Some countries are also getting into the private security business, hiring out small elements of their navies to escort commercial vessels along the most dangerous sections of the trans-Indian Ocean voyage.
In a paper to be released today, Mr Brown says there is a risk of a ''mini-arms race'' developing between pirates and the private security operators.
He says the government should do more to track former navy and army members who had become guns for hire on the high seas, where the law remains a quagmire of competing jurisdictions.
''National governments have some responsibility for how the taxpayer-funded military skills of these personnel are used - even when they leave the military,'' he writes. ''One way to begin addressing this risk is to require former military personnel to register their overseas employment in the security industry.''
He also wants Australia's customs, defence and foreign affairs agencies to join a push to design accreditation schemes for the new private armies and navies springing up on the oceans.
More than 140 private military security companies specialising in anti-piracy operations have been launched in the past 18 months.
Somali raiding parties have extracted $146 million in ransom money for captured ships and crews in the past year alone, fuelling a real estate boom in Somali towns and attracting investors who finance piracy operations for ransom shares.
While Australia contributes a ship to an international naval force patrolling the shipping routes, the range of the pirates' operations - more than 8.3 million square kilometres of ocean - makes it impossible for naval forces to contain the problem. Mr Brown says countries that hire out their military personnel risk being embroiled in ''disputes beyond their control''.
To get around laws banning weapons in ports, some private security operators have set up their own ''floating armouries'' on the high seas, from which guards collect their guns before embarking on a voyage.
Others have patrol boats, armed with machineguns, which they lease out.
"If unchecked, these fleets could be more akin to seaborne vigilantes than to private incarnations of naval counter-piracy forces," this report says.
Mr Brown says the rise in the use of outsourced naval personnel is fraught with particular problems as any state hiring out military personnel risks ''becoming embroiled in disputes beyond their control''.
Two Italian marines are in custody in India after killing two Indian fishermen they mistook for pirates.