An Australian woman detained last month in Yemen on suspected links to al Qaeda was released and was flying to Sydney with her two children, her Yemeni lawyer said.

"Yemeni security came and took her and her children to the Sanaa airport, where they handed them over to representatives from Australian intelligence," Abdel Rahman Barman said.

Shyloh Giddens, who was detained in April, was never formally charged with a crime, but it is believed she was held  over suspected links to al Qaeda, Barman said.

Giddens'two children, aged 5 and 7, had been kept under house arrest under the care of her housemates. The children will be accompanied by an Australian embassy representative on the flight to Sydney.

Yemeni government officials announced shortly after her detention was made public that they were holding several US and French students of Arabic on security grounds.

The Saudi-owned Arabic daily Al-Hayat cited unnamed Yemeni security officials saying that around 50 foreigners, including US, British, French, and Malaysian nationals, were being held on suspected al Qaeda ties.

Yemen, neighbour to top oil exporter Saudi Arabia, has been a Western security concern since the Yemen-based regional al Qaeda arm claimed responsibility for a failed December attempt to bomb a US-bound plane.

The impoverished state's Western allies and Saudi Arabia fear al Qaeda is trying to exploit instability in the fractious nation, with domestic conflicts in its north and south, to use it as a base to launch attacks in the region and beyond.

Giddens converted to Islam and moved to Yemen along with her two young children in 2006.

Australian authorities had cancelled her passport in April on security grounds, a spokeswoman from Australia's Department of Foreign Affairs and Trade said without giving further details, but added that Giddens had retained her citizenship.

Her two children, whose passports were confiscated by Yemeni authorities while they were under house arrest, were given back their passports upon arriving at the Sanaa airport. – Reuters