SOUTH Australian Senator Nick Xenophon snacked on McDonald's and table crackers as he awaited deportation from Malaysia for being a threat to national security.

The Independent Senator is due to arrive in Melbourne in the morning after he sparked a diplomatic incident when he was detained at Kuala Lumpur airport during unofficial parliamentary business.

The independent Senator was stopped immediately on arrival in Malaysia, held in custody for 16 hours and put under security detail.

Former prime minister Kevin Rudd told Sky News today that: "detaining any member of an Australian parliament is just unacceptable".

"I'm sure Bob Carr has the matter well in hand."



While he said that he would disagree with Senator Xenophon on a range of matters, he said Australia should be "robust" with Malaysia over the incident.



"I think we should be appropriately robust," he said.

"It is absolutely laughable - I was due to have a meeting with a senior Government Minister among others," Senator Xenophon said from an interrogation room where he was being held.

"The people detaining me have been polite but they told me the orders to get me out of the country immediately came from `high up'.

"They told me I am being deported under Section 81 of the Immigration Act, which says I pose a threat to the security of the country

"This was supposed to be a low-key visit by members of the major parties but now it has blown up into an international incident. It confirms all the concerns that have been raised about people being opposed to any kind of electoral reform."

His detainment triggered a diplomatic incident, with Foreign Minister Bob Carr demanding his immediate release.

"We are seeking a full explanation of this," he said. "We think it is sad for a friendly country to deport an Australian member of Parliament, who was up there for peaceful purposes.".

Australia's concerns were immediately raised with Malaysia's Foreign Minister, the Minister for Home Affairs and the Malaysian High Commissioner to Australia.

Austalian High Commissioner Miles Kupa was allowed to see Senator Xenophon late yesterday - bringing him a takaway meal to supplement the biscuits he was fed - and he was moved from an interrogation room adjoining female prison cells to an office area before being taken to an airport lounge.

Senator Xenophon co-authored an international observers' group report released last year on the Malaysian electoral system that was critical of gerrymanders and that called for significant electoral reform.

His deportation caused an Australian delegation of MPs to cancel their planned visit to the country. Liberal MP Mal Washer, Nationals Senator John Williams and ALP MP Steve Georganas were to join Senator Xenophon to meet Opposition Leader Anwar Ibrahim, as well as Malaysia's minister in charge of parliamentary affairs Mohammed Nazri ahead of Malaysia's elections.

Senator Xenophon joined the Customs queue on arrival at Kuala Lumpur but was told there were "irregularities" with his passport and was taken to an interrogation room.

He was told he was not allowed to make calls but managed to make a call to the Sunday Mail when he was briefly left unattended and send a photograph of himself.

"I am effectively a prisoner here," he said. "The whole situation is ridiculous; we are meant to be the closest of friends with Malaysia. We are meant to be having a people-swap deal on asylum seekers but so far it looks like the only person being swapped is me."

Senator Xenophon, who paid for his own trip, had planned to stay in Malaysia until Tuesday night.

He plans to hold a press conference upon his arrival into Melbourne.