MELBOURNE: An Indian-origin aviation worker in Australia who was sacked last year for posting pro-Islamic State messages on Facebook has told a court that his comments were "sarcastic".

Nirmal Singh was facing the 'Fair Work Commission' to argue that his dismissal was 'unfair' by his previous employer Aerocare and was seeking USD 7,000 in lost wages.

The Commission heard Singh had written "We All Support ISIS" above a shared post from HT (Hizb ut-Tahrir) Australia about the shooting of police account Curtis Cheng by Islamic youth Farhad Khalil Mohammad Jabar in Sydney.

There were five posts in total that concerned Aerocare, two of which included pictures of Prime Minister Malcolm Turnbull.

Under cross-examination by solicitor Stephen Hughes for Aerocare, Singh said he made the posts on Facebook under a different name and believed he was conversing with a "secret group".

However, two Aerocare employees who were Facebook friends with Singh, independently raised concerns about the posts with a manager.

Australian Federal Police, Perth Airport and the "client airline" of Aerocare were also made aware of the posts, and the airline requested Singh no longer be allowed to work around its planes.

After three meetings held over four days last October, Singh was told that Aerocare was terminating his employment for breach of their social media policy, and demanded he return his airside security pass to Perth Airport for cancellation.

At the Fair Work Commission hearing, Singh argued the posts were "sarcastic" in nature and he did not support Islamic State.

He said he deleted the posts and his Facebook "alias" profile after meeting with his manager.

"There were concerns I understood and I addressed those concerns by offering to delete the posts and the profile but how they breached the social media policy, I don't understand," Singh told the Brisbane hearing, from a video link in Perth.

Hughes asked if Singh was aware Australia was on high alert for a terrorist attack which was currently rated "probable".

"Absolutely and I support that," Singh replied.

Commissioner Jennifer Hunt wanted to review transcripts and receive some further written submissions before making her decision in writing.

Singh maintained he did nothing wrong by posting "We All Support ISIS" on Facebook and said he was in fact a member of a secret group against religious extremism.