Friends of an Australian couple detained in Iran for allegedly flying a drone over a military site without a permit have defended the "wonderful couple", who face up to six months' imprisonment inside the notorious Evin Prison.
The Department of Foreign Affairs and Trade is providing consular assistance to the families of Mark Firkin and Jolie King, who have been detained for more than two months in Tehran.
Foreign Affairs Minister Marise Payne said the government has been working to secure their release for more than a week. She said she travelled to Bangladesh last week to meet Iran's Foreign Minister Mohammad Javad Zarif but has not revealed details of those talks.
Mr Firkin and Ms King moved from NSW to Western Australia in 2015. They quit their jobs in April 2017 and less than three months later had embarked on an overland expedition destined for Britain.
To prepare for their epic adventure, Mr Firkin - formerly a builder in Coffs Harbour - and Ms King - previously a hairdresser in Newcastle - sold most of their possessions before embarking on several months around the north of Western Australia and the Northern Territory.
From Darwin, they freighted their troop carrier Toyota to Timor-Leste and drove into Indonesia, shipped their car to Malaysia and have driven overland through South-East Asia into Central Asia and Iran.
Intended to take in 36 countries and to confront "the stigma around going to some of the places ... and what the media kind of portrays about these areas and how safe they actually are", the journey was cut short in June by their imprisonment.
When the pair stopped posting on their Instagram account and to their YouTube channel, friends became concerned.
“You guys OK? It’s been a while," one follower wrote.
“What the hell is going on - these are extremely lovely people. I really hope they are fine and well," another wrote.
The couple's last post was from western Kyrgyzstan in late June.
"We definitely don't have anything to complain about," a comment from the couple's Facebook account read.
Their Instagram geolocation says that the pair are "Currently: Taking a Break."
Images from their website and social media presence over the past two years shows a number of images of the pair and their Toyota troop carrier taken by drone. But DFAT's Smart Traveller advice suggests photography in Iran, particularly around military installations, could be problematic in a nation with a risk of "arbitrary detention".
"It would be highly unlikely that the Government of Iran would allow the Australian Government to provide consular assistance to you if you are arrested or detained," the website reads.
"You may be at greater risk if you have a profile ... or if you undertake certain activities which could attract the attention of Iranian authorities. These may include travel off the beaten track, being present near sensitive sites [or] taking photographs."
Australian Michele Rankin met the "wonderful couple" in East Timor and spoke of their generosity.
"They spent a few days helping us to deliver much needed supplies to schools in remote areas ... thinking of you," she wrote on Facebook.
London's The Times has reported Ms King is believed to be imprisoned as a bargaining chip for a prisoner swap with Iranian woman Negar Ghodskani, who was extradited from Australia to the US and charged with a conspiracy to export prohibited technology to Iran.
Ms Ghodskani, 40, was arrested in Australia at the request of US authorities and gave birth in prison in Adelaide.
She has pleaded guilty to the charge, which carries a sentence of up to five years in a federal US prison.
"Let’s have an exchange. I’m ready to do it. I have the authority to do it," said the Islamic Republic's Foreign Affairs Minister Mohammad Javad Zafir in April.
Iran has yet to comment on the arrests or diplomatic attempts being made by Australia.
The arrests come weeks after Prime Minister Scott Morrison agreed to a US-led military effort to protect ships passing through the Strait of Hormuz, which is to the south-west of Iran.
About one-fifth of the world's oil passes through the Strait sees and Western nations are concerned about what Mr Morrison called "destabilising behaviour" affecting Australia's interests.