A Malaysian official has threatened to take "stern action" against Malaysian students in Australia who attend the Adelaide Festival of Ideas on Saturday where opposition leader Anwar Ibrahim is due to speak, according to an e-mail sent to students.

Mr Anwar has slammed the email under the name of Malaysia's Public Services Department saying it illustrates a "siege mentality" by Malaysia's ruling United Malays National Organisation.

Malaysia's opposition leader Anwar Ibrahim. Credit:Reuters

"They do not want the students to be exposed to other views because we are often labelled as pro-Communist and pro-Christian," Mr Anwar said in Kuala Lumpur before leaving for Australia.

"They cannot imagine that we have direct access to the students," he said.