Islamic Council of Queensland spokesman Ali Kadri said the graffiti was done between 2.30am and 4.30am on Wednesday at the Holland Park Mosque in Brisbane's south.
"The last person from the mosque who drove past and saw the wall was there at 2.30am and there was nothing there. The first members arrived for prayer at 4.30am and the graffiti was there,"he said.
"It's about fear,but more importantly,it points to a highly radicalised person with the references to Brenton Tarrant[Christchurch shooter] and St Tarrant.
"The'remove kebab'phrase was written on Brenton Tarrant's gun in Christchurch and comes from a Serbian anti-Islam song about the massacre of Muslims in Bosnia.
"It is related to the neo-Nazi and white supremacist movements. Whoever has done this is no child,they have been radicalised."
Detectives examined the scene on Wednesday and looked for DNA. They were expected to collect the mosque's security camera footage later in the day.
The mosque was in the process of removing the graffiti.