Out of control bushfires forced residents in eastern Australia to flee their homes on Saturday, as other parts of the country braced for a heatwave due next week.

Two gay Saudi journalists who sought asylum in Australia after being threatened at home over their relationship have been held for weeks at an immigration detention centre, their lawyer said Wednesday.

The UN's top rights official urged Australia to reform its criminal and refugee detention systems on Tuesday, just days after the country's prime minister took a veiled swipe at the international body.

An Iranian student detained in Australia for 13 months on accusations of circumventing US sanctions on military equipment has returned to Tehran after being released, state television reported Saturday.

The news came shortly after Canberra said an Australian couple held in Iran on spying charges had flown home.

Iran has charged three detained Australians with spying, judiciary spokesman Gholamhossein Esmaili said on Tuesday, cited by Tasnim news agency.

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.

Australia on Saturday warned foreign officials in the country against undermining the right to free speech, following a confrontation between students backing Beijing and pro-Hong Kong democracy activists at a university rally.

Australia's ruling conservative coalition is set to secure a governing majority in its shock election victory over the centre-left Labor Party, the national broadcaster ABC projected Monday.

Exit polls in Australia's climate-dominated election campaign pointed on Saturday to a win for Labor after six years of conservative rule.

Between 16 and 17 million people were expected to vote across the vast island-continent in a bitterly fought election that may be the first anywhere decided by climate policy.

Australia's political leaders made last-gasp pitches to voters on Friday, on the eve of an election that polls show is going down to the wire.