Britain could send military reinforcements to the Gulf if the dispute with Iran escalates, Defence Secretary Philip Hammond has said.
He said the decision to send HMS Argyll as part of an international flotilla of warships through the sensitive Strait of Hormuz on Sunday sent a "clear signal" to Tehran.
Iran has threatened to close the strait - through which 35% of the world's tanker-borne oil exports pass - in retaliation for sanctions against its oil exports.
Asked if more resources could be sent, Mr Hammond said: "The UK has a contingent capability to reinforce that presence should at any time it be considered necessary to do so."
He was speaking at a press conference in London following the annual round of talks between UK and Australian foreign and defence ministers.
Australia's foreign minister Kevin Rudd said his country would enforce the same ban on Iranian crude oil exports agreed by the European Union yesterday.
He and defence minister Stephen Smith will attend today's National Security Council meeting.
David Cameron, Angela Merkel and Nicolas Sarkozy have issued a statement amid EU oil sanctions imposed against Iran on Monday.
The move came after Britain joined the United States and France in sending a flotilla of warships through the sensitive Strait of Hormuz as tensions escalate of over the regime’s controversial nuclear programme.
The statement said: "Today, the EU agreed an unprecedented package of sanctions on Iran, including a full ban on Iranian oil exports.
"Our message is clear. We have no quarrel with the Iranian people. But the Iranian leadership has failed to restore international confidence in the exclusively peaceful nature of its nuclear programme. We will not accept Iran acquiring a nuclear weapon. Iran has so far had no regard for its international obligations and is already exporting and threatening violence around its region."