Jolie King and Mark Firkin had been documenting their journey on social media

Two Australians detained in Iran were named on Thursday as a travel-blogging couple, who were arrested while making an overland trip from their home country to Britain.

Perth-based Jolie King and Mark Firkin had been documenting their journey on social media for the past two years but went silent after posting updates from Kyrgyzstan and Pakistan about 10 weeks ago.

"Our families hope to see Mark and Jolie safely home as soon as possible," a statement released on behalf of their relatives said.

Before setting off, the couple had written on their blog that they "can't wait to share all of our experiences and the beauty of all the different destinations and countries we will be visiting".

Australia first revealed on Wednesday that three of its citizens had been seized by authorities in Tehran.

The Times of London reported the third person was a British-Australian academic who studied at Cambridge University and was working as a lecturer in Australia when she was arrested in Iran nearly a year ago.

News of the arrests came after Australia announced it would join a US-led mission to protect shipping through the Strait of Hormuz, with tensions high in the Gulf region.

The Times also reported that Mr King and the other woman were being held in Tehran's Evin prison and that one of them had been told she was being held as part of a plan to facilitate a prisoner swap.

Already difficult relations between Iran and the US -- and American allies -- have threatened to boil over since President Donald Trump in 2018 abandoned a deal to limit Tehran's nuclear programme, and Iran resumed some proscribed nuclear activities.

Australian Prime Minister Scott Morrison last month announced a "modest" Australian contribution to the US-led Gulf mission -- including a frigate, a P8 maritime surveillance aircraft and support staff -- which will also involve British forces.

Asked about detained Australians, Morrison said Thursday the government would "continue to pursue these matters in the interests of the Australians at the centre of these cases".

"We will do that carefully and we will do that in close consultation through our officials who have been part of this process now for some time," he told reporters in Canberra.

Australia's Department of Foreign Affairs and Trade said it was providing consular assistance to the detained trio and has urged Australians to reconsider travelling to Iran.

Earlier this week, the Australian government updated its travel advice for Iran to "reconsider your need to travel" and "do not travel" to areas near the border with Iraq and Afghanistan.

It was not immediately clear if any of the three have been charged.