Abu Dhabi, Aug 1 (IANS): UAE'S flag carrier Etihad Airways on Tuesday said it was assisting Australian police with their investigation into a suspected terrorism plot to bring down a plane, the media reported.

"The Etihad Airways aviation security team is assisting the Australian Federal Police with its investigation and the matter is ongoing," the airline said in a statement on Tuesday.

"Etihad is complying fully with the enhanced security measures at airports in Australia and monitoring the situation closely," the BBC quoted the statement as saying 

Police have been searching five properties across Sydney after four men were arrested in raids on July 29.

Local media reported the men planned to use poisonous gas or a crude bomb disguised as a meat mincer, but police have not confirmed details of the alleged plot.

Police did not name the airline involved, but officials have described the operation as "sophisticated".

On July 30, a magistrate gave permission for an additional period of detention, meaning the four can be held for up to seven days without charge, the BBC reported.

No charges have been laid against the men.

Australian airports have increased their security measures and passengers were left waiting in lengthy queues after being advised to arrive earlier than usual.

The national terror threat level remains at "probable".