An Australian lawmaker was detained at the Kuala Lumpur airport Saturday and is expected to be deported acccording to an activist.

Nick Xenophon, an outspoken independent Senator, was detained at the international airport near the capital Kuala Lumpur upon his arrival from Melbourne.

"He informed me that he is being deported," Ambiga Sreenevasan, a lawyer and co-chair of electoral reform group Bersih, told AFP after she spoke to Xenophon early Saturday.

The Malaysian government is yet to comment on the circumstances surrounding Xenophon's detention but Ambiga said it appeared to be "under the Security Offences Act".

"(Authorities) said he is a security risk," she added.

Xenophon, who has travelled to Malaysia several times, was to meet Bersih members and others including opposition leader Anwar Ibrahim and Election Commission officials next week, Ambiga said.

Australia's Foreign Minister Bob Carr said Australian officials were in touch with Xenophon, as well as Malaysia's foreign and home ministers, and were seeking his "swift release" from custody.

"Senator Xenophon's detention is a surprising and disappointing act from a country with which Australia routinely maintains strong diplomatic relations," he said in a statement.

The Security Offences (Special Measures) Act, or SOSMA, was introduced in Malaysia last year to replace the much-criticised colonial-era Internal Security Act, which allowed indefinite detention without trial.

Prime Minister Najib Razak has touted SOSMA and other reforms to show he is granting more civil liberties, but rights group have criticised the new act, saying it still gives broad powers to detain people for too long.

Malaysia has deported several foreigners in recent years. Among them was a French lawyer representing a human rights group in an inquiry into alleged corruption linked to Najib.