The Australian Defence Force's chief imam signed a petition protesting against a push by former prime minister Tony Abbott to ban Islamist extremist group Hizb ut-Tahrir.

Sheikh Mohamadu Nawas Saleem added his name to this petition in February 2015 after Mr Abbott proposed to prohibit the group, which campaigns for a global Islamic caliphate based on sharia law.

Now, federal Attorney-General George Brandis is again rejecting a call for that group to be banned, despite its recent calls for ex-Muslims to be killed and its advocacy of domestic violence.

Scroll down for video

Defence's chief imam Sheikh Mohamadu Nawas Saleem signed a pro-Hizb ut-Tahrir petition

The Australian Defence Force's chief imam signed the petition in February 2015

His name was on a list of Muslim community leaders opposed to a push to ban Hizb ut-Tahrir

The Defence Force's chief imam has been paid $717 a day since mid-2015 for religious advice

Attorney-General George Brandis has declared Hizb ut-Tahrir won't be banned in Australia

The Turnbull Government is reluctant to ban Hizb ut-Tahrir only three weeks after Indonesia, the world's largest Muslim-majority nation, announced it would prohibit the politically-motivated Islamist group.

In early 2015, Sheikh Saleem endorsed a petition which accused Mr Abbott of making 'politically convenient threats to 'tackle' and 'crack down' on Islamic groups such as such as Hizb ut-Tahrir ... whose only 'crime' has been to criticise the Abbott government's stance towards Muslims domestically and abroad'.

He is on the board Imams Victoria and since June 2015 has received $717 a day as a member of the taxpayer-funded Religious Advisory Committee to the Services, which advises the Australian Defence Force.

The petition claimed that Hizb ut-Tahrir disavowed and have never supported terrorist acts, but it declined to mention how they are banned in Germany, The Netherlands, Russia and a range of Muslim-majority nations including Pakistan, Bangladesh and even Saudi Arabia.

Hizb ut-Tahrir spokesman Uthman Badar told a forum that ex-Muslims deserved to be killed

Now Senator Brandis has declared the group will not be banned, even though Daily Mail Australia in March caught its spokesman Uthman Badar on camera saying people deserved to be killed for leaving Islam.

'The ruling for apostates as such in Islam is clear, that apostates attract capital punishment and we don't shy away from that,' Badar said at Bankstown, in Sydney's west.

Justice Minister Michael Keenan referred his extraordinary admission to the Australian Federal Police.

Despite this, Senator Brandis has again rejected listing Hizbut Tahrir as a terrorist organisation in Australia.

The attorney-general had sought fresh advice from the Australian Security Intelligence Organisation last week.

Earlier this month, Indonesian security minister Wiranto said the Indonesian activities of Hizbut Tahrir had 'clearly caused conflict in society' and threaten the integrity of his country.

Senator Brandis told reporters in Canberra on Tuesday he had sought the professional advice of security agencies about the group on a number of occasions, including last week.

It was the 'strong view' of ASIO analysts that Hizb ut Tahrir Australia - which describes itself as a 'political party' on its official website - did not fit the definition of a terrorist organisation in the criminal code.

There are 23 bodies listed as terrorist organisations in Australia.

Before a group is listed the attorney-general must be satisfied on reasonable grounds that the organisation is 'directly or indirectly engaged in preparing, planning, assisting or fostering the doing of a terrorist act, or advocates the doing of a terrorist act'.

Hizb ut-Tahrir held a conference at Campsie, in Sydney's west earlier this month, asking if Muslims in Australia will be imprisoned in concentration camps.

In April, Hizb ut-Tahrir Women posted a video arguing that Muslim men could hit their wives with a stick if they disobeyed them, describing domestic violence as a 'beautiful blessing'.