The incident is latest in a series of Westerners to be seized by authorities in Iran. (Representational)

The Australian government on Wednesday said three citizens had been detained in Iran, the latest in a series of Westerners to be seized by authorities in Tehran.

"The Department of Foreign Affairs and Trade is providing consular assistance to the families of three Australians detained in Iran," a spokesperson told AFP.

"Due to our privacy obligations, we will not comment further."

The Times of London earlier reported that two British-Australian women were being kept in Tehran's Evin prison.

Australian public broadcaster ABC said that the Australian boyfriend of one of the women had also been detained.

It is not clear if the three have been charged. One of the women is reported to have been in detention for up to a year.

The news of the trio's detention comes after Australia announced that it would join a US-led mission to protect shipping through the Strait of Hormuz.

Prime Minister Scott Morrison in August announced a "modest" contribution to the controversial mission -- including a frigate, a P8 maritime surveillance aircraft and support staff -- which will also involve British forces.

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.

Already difficult relations with Iran have threatened to boil over since US President Donald Trump abandoned a deal to limit Iran's nuclear programme in 2018.

Iran has responded by resuming some prescribed nuclear activities.

Meanwhile, a rising number of dual nationals have been detained, in what many see as a ruthless diplomatic strategy.

Analysts see the arrests as a tactical ploy to gain leverage, or as part of the murky politics in Iran -- with hardliners in the judiciary and the security apparatus scuttling the more conciliatory approach of moderates.