By Grace Crivellaro and Tess Ikonomou in Canberra

A flight bound for Sydney has left Dubai carrying Australians who were trapped in the Middle East after war broke out.

The plane is expected to land at Sydney Airport after 10.30pm on Wednesday evening.

It is unknown how many Australians are on the flight, with about 24,000 of the nation’s citizens still stranded in the United Arab Emirates after flights were grounded due to Iranian retaliatory attacks following US-Israel assaults.

Foreign Minister Penny Wong earlier confirmed the flight ahead of its departure but warned the situation remained “perilous”.

“This is a consular crisis that dwarfs … any that Australia has had to deal with in terms of numbers of people,” she told ABC radio.

People are advised to stay in contact with their airlines as the situation is rapidly changing.

While some limited flights are resuming out of the UAE, services are largely grounded, leaving tens of thousands of Australians potentially trapped for weeks.

Asked if people could fly out of the Middle East via Saudi Arabia or Oman, the foreign minister said all options were being considered while noting the conflict had spread to the broader region.

Senator Wong maintained commercial flights remained the best way to get large numbers of people back to Australia.

Prime Minister Anthony Albanese spoke with the president of the UAE, Mohammed bin Zayad al Nahyan, on Tuesday night and thanked him for the hospitality shown to Australians stuck in transit.

The prime minister also spoke with his New Zealand counterpart Christopher Luxon about consular issues arising from the war, which began when the US and Israel began hitting Iranian targets.

United Nations special rapporteur Ben Saul said it was “crystal clear” the attackers’ actions were an unlawful, armed aggression against Iran.

“Every death in Iran is a violation of the human right to life as well under international human rights law,” he told AAP.

“These aren’t acts in self-defence because Iran has not attacked either country and is not about to imminently attack them and the security council hasn’t given any authorisation.”

Professor Saul accused the Australian government of “trashing” the rules-based world order while it dodged questions about the legality of the attacks.

Australia was one of the first countries to back the strikes by US and Israeli forces over the weekend, although government ministers have said it was up to the instigators to argue the legal basis for their military action.

Tehran has retaliated with a barrage of drones and missiles aimed at neighbouring states, targeting oil and natural gas infrastructure.

About 115,000 Australians are believed to be stranded in the Middle East as the conflict continues to disrupt air travel.

Australia’s embassy in Saudi Arabia has warned citizens in Riyadh, Jeddah and Dhahran to shelter in place, while a defence base in the UAE housing Australian troops was previously hit in an Iranian attack.

Opposition industry spokesman Andrew Hastie, an Afghanistan war veteran, said US President Donald Trump’s four to five-week timeline for action in Iran was optimistic.

“I think the rules-based global order is dead and buried and so these sorts of legal arguments are nice, but we live in the world of reality,” he said.