The Associated Press

In this Wednesday, Dec. 8, 2010 photo, Australian senator Nick Xenophon, right, walks with Malaysian opposition leader Anwar Ibrahim at the Parliament House in Kuala Lumpur, Malaysia. Authorities on Saturday, Feb. 16, 2013 detained and planned to deport Xenophon who flew into Malaysia to highlight his concerns about upcoming elections. (AP Photo) MALAYSIA OUT

By ROD McGUIRK Associated Press

CANBERRA, Australia (AP) — Australia has demanded an explanation from Malaysia for why it turned away an Australian senator from his fact-finding mission to investigate the Southeast Asian country’s electoral system ahead of elections due within months, the prime minister said Sunday.

Nick Xenophon, an independent South Australia state senator, returned from Malaysia on Sunday saying he had been deported on the orders of the ‘‘highest levels’’ of the Malaysian government for his support of democracy reformers.

He told reporters on arrival at Melbourne International Airport after an 8-hour flight that he had become the first Australian lawmaker ever to be deported from any country when he was turned away by on authorities on arrival at Kuala Lumpur on Saturday.

Prime Minister Julia Gillard revealed that her government made ‘‘immediate and strenuous representations’’ for Xenophon to be allowed to stay in Malaysia.

‘‘I was surprised and disappointed to see the treatment of Senator Xenophon yesterday,’’ Gillard told reporters.