Australia will send troops, a plane and a warship to help guard the Strait of Hormuz in the Middle East, Prime Minister Scott Morrison has confirmed.
Australia's decision to join an international military campaign to help guard oil tankers is a "sensible" response to attacks in the Strait of Hormuz, a leading security analyst says.
The Australian Defence Force will contribute about 200 troops, a surveillance plane and a warship to a United States-led effort to protect sea lanes from Iranian interference.
Australian Strategic Policy Institute executive director Peter Jennings said Australia's contribution to the mission was "valuable and meaningful".
"I think the message that we need to give to Iran is that the international community wants to see the safety of shipping going through the Strait of Hormuz and that's so important to us that were willing to put lives on the line to protect those ships," he told SBS News.
Mr Jennings said the heightened tensions in the Gulf is the latest sign the international rule of law is under strain.
"This is the moment for the consequential democracries I think to stand up and say enough is enough," he said.
Prime Minister Scott Morrison said the "modest, meaningful and time limited" contribution was in Australia's national and economic interests.
"The government has decided it's in Australia's national interests to work with our international partners to contribute to an international maritime security mission ... in the Middle East," he told reporters at Parliament House on Wednesday.
At least 15 per cent of crude oil destined for Australia - and up to 30 per cent of refined oil - transits through the Persian gulf.
"So it is a potential threat to our economy," Mr Morrison said.
The warship will be redirected from an anti-piracy operation in the Middle East, while the Australian troops will be based in the headquarters that are coordinating the US-led maritime security mission.
Initially, Australia will be involved for at least six months.
However, the prime minister made it clear the mission could be extended.
The deployment raises questions about the rules of engagement, and what Australian troops will be able to do in response to any aggressive behaviour that comes their way.
Australia's Chief of the Defence Force Angus Campbell was asked what the frigate would do if a commercial ship was seized, and whether his troops would be allowed to open fire.
"Our people are very well trained and they will be operating under international law," General Campbell told reporters.
"Their presence will be to support security of shipping and freedom of navigation."
Labor supports the decision to send Australian forces to the Strait of Hormuz.
Acting opposition leader Richard Marles said the size of the deployment and tight timeframe were both appropriate.
"Freedom of navigation for Australia as a trading island nation is completely central to our national interest," Mr Marles told reporters in Sydney.
"The vast bulk of our trade goes by sea and trade forms a very large part of our national economy."
So far the US-led international coalition includes the United Kingdom, Australia and Bahrain.
But the mission will be a key topic of discussion when Mr Morrison meets the leaders of the seven wealthiest advanced countries in France this weekend.
Mr Morrison has spoken to the UK's new leader Boris Johnson several times ahead of his trip to Biarritz.
"(The G7 meeting) is an important time, I think, to reinforce these shared values in today's world - democracy, respect for human rights, international law and free markets," he told reporters.