Last month the Australian government intercepted two boatloads of Sri Lankan asylum seekers supposedly bound for Australia. While those on one boat were sent back to Sri Lanka after “enhanced processing”, the fate of the second is in limbo on the high seas.

The High Court heard yesterday that the 153 Tamil asylum seekers now being held on board an Australian Customs vessel were seized before they could enter Australian waters. While we wait for the hearing to continue, Crikey takes a look at the limits of the long arm of Australia’s laws.

Where does Australian sovereignty end?

Australian sovereignty extends 12 nautical miles from the Australian coastline or islands in a belt of water called the Territorial Sea. These waters, the seabed below it and the airspace above it are considered part of Australian territory and are subject to our laws and regulations.

Where was the boat?

Despite initial reports that the boat was stranded up to 170 nautical miles off the coast of Christmas Island, Solicitor-General Justin Gleeson SC told the High Court yesterday that the vessel had been intercepted within Australia’s contiguous zone, a stretch of water extending another 12 nautical miles beyond the limits of the Territorial Sea. This places the boat within 24 nautical miles of Christmas Island at the time of boarding.

Does Australia have authority there?

While the contiguous zone is not part of Australian territorial waters, the Australian government has the authority to intercept any vessel it believes is infringing on its customs, fiscal, immigration or sanitary laws. In this instance, the decision to board a vessel suspected of transporting people into Australian waters without authorisation falls within the powers of the Australian authorities.

Where does the Migration Act come in?

According to the Solicitor-General, it doesn’t — as the boat never reached Australian territorial waters, the Migration Act is “inapplicable” to the 153 asylum seekers on board the vessel, offering them no protection under Australian law.

Do the refugees have any rights under Australian law?

Refugee rights activists maintain that the Australian government still has clear obligations under the international refugee convention to process refugee claims and provide them with access to legal aid. On Monday, 53 human rights scholars released a signed statement saying that the so-called enhanced screening processes employed by Australian authorities “do not comply with minimum standards on refugee status determination under international law”, pressing for greater judicial scrutiny and some form of oversight process.

What happens now?

ANU professor of international law Donald Rothwell says that while the government has pledged to give at least 72 hours’ written notice before surrendering the boatload of asylum seekers to the Sri Lankan authorities, it has made no such promises regarding sending the 153 refugees elsewhere.

“The undertaking as it stands at the moment only relates to Sri Lanka,” he said.

Rothwell suggests that the Commonwealth may explore the possibility of an agreement to settle the asylum seekers in a third-party country such as Cambodia or India in a move reminiscent of the actions taken by the Howard government in the wake of the 2001 Tampa affair.

The case is expected to go before the full High Court for a directions hearing within 21 days.