Ian Macdonald, dubbed by the Australian press "Sir Lunchalot," ended a 22-year career Friday with his resignation, The (Sydney) Morning Herald reported.
His resignation from Parliament came three days after he quit the Cabinet post of state development and major events minister, the newspaper said.
Australia's Independent Commission Against Corruption says it has been investigating aspects of expense claims Macdonald made after a trip to Dubai in 2008 with his wife and friends.
That report is expected to be sent to the country's premier in the next few days, the Morning Herald reported.
Macdonald had not been due to face re-election until 2015.