Washington's top diplomat says while America is not postured ‌for ground forces in Iran, President Donald Trump does have those options.

US Secretary of State Marco Rubio says Iran is suffering a tremendous amount of damage, and warns the hardest hits are yet to come for the country.

The US has announced the deaths of a further two service members in an attack by Iran, bringing the US death toll to six.

The federal government has confirmed an airbase used by Australian personnel has been hit by an Iranian drone strike.

The government says the Al-Minhad base just outside Dubai was struck on the first night of the conflict.

Deputy Prime Minister Richard Marles says all personnel are safe and accounted for.

Meanwhile, the government says it's working on contingency plans to assist Australians stranded in the Middle East, with air space closures forcing the cancellation of thousands of flights.

Shadow Attorney General Michaelia Cash is calling on the government to improve its communications with Australians stranded in the region.

The weather bureau's monitoring a tropical low off the far north Queensland coast which could develop into a cyclone from Thursday.

The system over the Coral Sea is about 900 kilometres east of Cairns, and the bureau says it's expected to move towards the coast but its exact path is unclear.

Lebanon's government has banned military activities by Hezbollah after the militant group opened fire on Israel to avenge the killing of Iran's supreme leader.

In response to those attacks, Israel says it's hit Hezbollah targets in Beirut, including a financial institution linked to the militant group, senior Hezbollah officials as well as weapons stockpiles and command centres.

The Lebanese government has declared Hezbollah's operations unlawful, and is again demanding the group hand over its weapons.

Meanwhile six US service members have died from Iranian attacks, according to US officials.

Deputy Prime Minister Richard Marles says memorial services in Australia mourning the death of Iran's former leader are inappropriate.

Ayatollah Ali Khamenei was killed in recent days during the US-Israeli air strikes in Tehran.

A number of Shiite mosques and Islamic institutions in Sydney and Melbourne have been holding public memorials and prayer sessions mourning the death.

The weather bureau says a tropical low - about 900 kilometres east of Cairns - has a moderate chance of reaching cyclone strength from Thursday.

It comes amid widespread flood warnings across already-sodden north Queensland catchments, with flood watches covering most of the Cape York Peninsula and parts of the north-east tropical coast between the Daintree down to Townsville.

The war in the Middle East continues to intensify with the US and Israel ramping up air strikes in Iran focusing on the capital Tehran.

The war's also spread to Lebanon with dozens of people killed by Israeli strikes in retaliation for attacks by Hezbollah in Israel.

Iran has also targeted energy sites in Saudi Arabia and Qatar.

US president Donald Trump says the "big wave" is yet to come in the US-Israeli war with Iran, and named his rationale for the strikes on the country, including destroying its missile capabilities and its navy, and preventing it from ever having a nuclear weapon.

UK Prime Minister Sir Kier Starmer says the UK won't join US and Israeli strikes in Iran but says the country is taking defensive action.

In an address to the House of Commons he said the US could now use its bases in the gulf region as a launching pad to carry out attacks on Iran's weapons infrastructure.

Canada's Prime Minister, Mark Carney, will fly into Australia today for a three-day visit starting in Sydney.

He'll then head to Canberra, where he'll meet Anthony Albanese and address federal parliament. The two leaders are set to focus on bolstering economic and strategic ties as well as deepening defence cooperation.

Mr Carney's drawn global attention for recent speeches calling for middle powers to band together in the face of the ruptures caused by the Trump administration.

The war in the Middle East continues to intensify, with the US and Israel ramping up air strikes in Iran focusing on the capital Tehran.Iranian human rights organisation Hengaw says 1500 people have been killed in Iran including 200 civilians, while the war has also spread to Lebanon with dozens of people killed by Israeli strikes in retaliation for attacks by Hezbollah in Israel.

Iran's also targeted energy sites in Saudi Arabia and Qatar.  

Donald Trump says the US had the capability to carry out operation Epic Fury for far longer than the four to five weeks initially projected.

The US president named his rationale for the strikes on Iran – including destroying its missile capabilities and ensuring it couldn't fund regional proxies - without specifying regime change.

Meanwhile Israel's prime minister Benjamin Netanyahu says his country will continue action against Iran as long as necessary, claiming he and President Trump are saving the world in doing so.

The French President has announced France will increase its nuclear arsenal, and allow jets armed with nuclear warheads to be deployed to allied countries temporarily.

In a speech that had been planned before the outbreak of conflict in Iran, Emmanuel Macron said France's nuclear arsenal would help Europe's defence and independence.

The war in the Middle East continues to intensify after Israeli and US warplanes launched a fresh wave of strikes across Iran on Monday.

The Hengaw Organisation for Human Rights says 1,500 people have been killed in Iran so far, including 200 civilians.

While the Lebanese Health Ministry says at least 31 people have been killed by Israeli attacks in Beirut and southern Lebanon.

Israel says it was responding to attacks by Hezbollah, and also denied it breached international law in launching the military offensive against Iran with the US.  

Meanwhile, US President Donald Trump says joint American-Israeli strikes against Iran were the last and best chance to prevent threats from the regime.

In his first comments at a public appearance since the initial strikes that killed Iran's Supreme Leader, Mr Trump has claimed Tehran refused to cease its nuclear ambitions.

He says the objectives of the operation in Iran are clear, including destroying its missile capabilities and its navy, and preventing it from ever having a nuclear weapon.

He's also vowed that the largest wave of aerial strikes against Iran is yet to come.

Some flights to and from the Middle East are slowly resuming as the conflict continues to affect the travel plans of thousands of Australians.

While Emirates has cancelled all flights from Sydney to Dubai today, as well as morning flights from Melbourne and Brisbane, evening departures from Melbourne, Brisbane, Adelaide and Perth are all still scheduled.

Qatar Airways has cancelled four flights from Doha to Australia, while Qantas says there's currently no disruption to its flights to Europe via Singapore.

Australians have rushed to service stations after being warned the war in Iran could lead to petrol prices surging by as much as 30 cents a litre.

If the conflict drags on, experts say it's likely to drive up inflation, push interest rates higher and increase the cost of some household products.

Roughly 20 per cent of the world's oil flows through the Strait of Hormuz and any closure could mean more pain at the petrol pump.

Iran has suffered a 3-nil loss to South Korea in their opening match at women's soccer's Asian Cup on the Gold Coast.

Despite the concerns of the attacks on their country by the US and Israel, the Iranians produced a solid defensive effort in the first half to trail 1-nil at the break, before conceding two second-half goals

The Iranians will face Australia at the same venue on Thursday.

Listen to the latest updates from ABC News

Listen to the latest updates from ABC News

Listen to the latest updates from ABC News

Listen to the latest updates from ABC News

Listen to the latest updates from ABC News