13/01/2017 1:38 PM AEDT | Updated 13/01/2017 2:19 PM AEDT

Exclusive: DFAT Overcharged $14,400 For Sussan Ley's U.S. Trip

The foreign affairs department made a mistake, leading to massive $76,000 bill.

Sussan Ley has stood aside pending investigations.

The Department of Foreign Affairs has admitted to a big accounting error which saw embattled health minister Sussan Ley's claim for a seven-day trip to the U.S. the trip blow out by $14,413.

Ley's office revealed that $9127 in "overstated" transport costs was wrongly claimed during the trip, laying the responsibility with DFAT and stressing that Ley did not in any way benefit from the mistake. The department has confirmed their error to The Huffington Post Australia, and additionally revealed they mistakenly overcharged $5285 for meals and accommodation on the same trip.

Ley, who was this week temporarily sidelined as health minister as an investigation into her travel expenses opens, claimed $76,133.96 for a trip to the U.S. from February 15 to 21, 2016. Her latest expenditure report on the Department of Finance website shows she racked up $10,876 per day on the trip to the U.S. to "lead the MedTech stream of the Australia-US Business Week and conduct a series of bilateral meetings". The claim for the trip, which took in Houston and San Francisco, included $42,095 on fares, $11,230 on accommodation and meals and $21,271 on ground transport.

The expensive trip generated news headlines and further controversy for Ley, but HuffPost Australia has learned the figure was dramatically overstated and that the minister may have been unfairly criticised.

A DFAT spokesperson confirmed to HuffPost Australia that "an administrative error" was made when the department was "seeking reimbursement from the Department of Finance for costs" associated with Ley's trip.

"As a result, DFAT overcharged the Department of Finance by AUD14,413.70, comprising overcharges of AUD9127.84 on ground transport and AUD5285.86 on accommodation and meals," the spokesperson said.

"The administrative error was identified during normal checks and is being rectified."

Based on figures provided by Ley's office and DFAT, the stated overall cost of Ley's U.S. trip should have been $61,720, not $76,133.96. The $21,271 bill for ground transport should actually have been $12,143.57 and the bill for accommodation and meals should have been $5944.50, not $11,230.36.

The expenditure report where the trip details were outlined says information contained is "expenditure paid by the Department of Finance", suggesting the "overstated" figure $21,271.41 has been paid out already.

Department of Finance
Expenses claimed by Ley for her USA trip

In a statement, the Department of Finance said it had "identified a duplicate charge during the routine acquittal process" and that the "final cost of the trip will be reported in the reporting period 1 January - 30 June 2017."

In response to questions from HuffPost Australia, a spokesman for Ley stressed the mistake came in dealings between DFAT and the Department of Finance, and that neither Ley nor her office gained any benefit or extra money because of the error.

"The mistake was made by [the Department of Foreign Affairs and Trade] because it used duplicate invoices to overstate the costs of the Austrade organised trip. It had nothing to do with Ms Ley or her office," he said in an email.

"The Department of Finance has advised of the mistake and the incorrect allocation of cost against Ms Ley's trip will be rectified."

The spokesman said Department of Finance had advised Ley's office that the transport costs were "overstated by $9,127 because of duplication of invoices provided."

Ley's office advised she was accompanied by two staff on the U.S. trip, but did not answer questions about the specific breakdown of ground transport costs.

Ley on Monday announced she would step aside from Cabinet pending an investigation into her expenses. In the last week, it has been revealed that Ley chartered a $12,000 private jet and chartered and piloted planes herself rather than take inexpensive commercial options, that she'd bought a Gold Coast apartment while on a taxpayer funded trip, that the apartment was purchased from a Liberal Party donor, that her husband owned a business just nearby that apartment, and that she'd billed taxpayers for New Year's Eve Gold Coast flights.