Treasury Secretary Ken Henry ended his long public service career on Tuesday as the federal government announced his resignation from office following more than 25 years of tax reforms advocacy in Australia.

In revealing Henry's departure from office, Prime Minister Julia Gillard described him as one of the greatest of all Treasury secretaries and was a mainstay in decades-long development of Australia's taxation policy.

Ms Gillard hailed Henry's key contributions in pushing Australia to its present form of prosperity, which she said was largely brought about by his long tenure in the Treasury Ministry and where he also served as secretary for ten years.

Henry was appointed to the top job of the Treasury department in 2001 by then Liberal Prime Minister John Howard and retained his post in 2006.

The treasury secretary had a falling out with Mr Howard despite his reappointment and gravitated towards Kevin Rudd, who eventually assumed the leadership of the Australian Parliament when the Labor Party took power during the 2007 federal elections.

Again, Henry kept his job and went on in introducing controversial tax measures that included the yet-to-be-adapted 138-point Henry Tax Review, the dumped resources super profits tax and the still contentious minerals resource rent tax.

Yet his exit now came out amidst speculations that he was indeed on his way out before the promulgation of the country's budget next year and the revived debate on the new mining tax that mining firms such as BHP Billiton, Rio Tinto and Xstrata now labelled as deceptive for its grey provisions on state royalty taxes.

Ms Gillard said that Henry's resignation would become effective by the onset of the new year and most likely to replace him is current Federal Climate Change Minister Martin Parkinson, who also had a stint as deputy chief of the Treasury department.