Mrs Palin, the Republican vice-presidential nominee, released two years' worth of tax returns last week that did not list the per diem payments she received since becoming Alaska governor in December 2006.

She collected nearly US$17,000 (S$25,000) during that period for 312 nights spent in her Wasilla home about an hour's drive from Anchorage, according to state travel records.

Mrs Palin listed 157 days spent in Anchorage during 2007 on her travel forms. Ms Garnero said Mrs Palin's work place as governor is considered to be Juneau, so she filed for the per diem payments when she stayed at her home in Wasilla.

But state officials consider changing an employee's work station when they spend most of their time in another area, she said. That review will occur for Mrs Palin, Ms Garnero said, which may require Mrs Palin to report future per diem payments as income.

'That's something we need to confer with the governor's office on,' said Ms Garnero, who said she was not aware of the number of days Mrs Palin spent working in Anchorage.

A typical work year for most employees is 260 days in a calendar year, but Ms Garnero said the governor's staff told her on Tuesday that her work year is considered 365 days because she is on call around the clock.

That would mean Mrs Palin spent about 43 per cent of last year working in Anchorage, and would allow the governor to continue receiving per diem payments that aren't taxed when she stays at her home, Ms Garnero said.

The final decision likely will be made by the Internal Revenue Service, said Mr Allen Bingham, an Anchorage accountant and member of the Alaska Society of Certified Public Accountants' taxation committee. IRS officials could determine that Mrs Palin owes taxes on past and future per diem payments, he said.

Mr Bingham said Mrs Palin's situation is unusual because she claimed such a large number of days working away from Juneau, something that would typically raise red flags when considering whether the per diem should be considered income.

'It's certainly one of those things that some of us have raised our eyebrows about,' he said.

Mrs Palin released her tax returns last week, which revealed that she and her husband underpaid their estimated taxes with an April extension and likely will owe interest. The per diem payments were not included as income in those returns.

A spokesman for Mrs Palin did not immediately return a telephone call or e-mail. However, the Palins had asked Washington, DC, lawyer Roger Olsen to review their tax returns before they made them public last week.

Mr Olsen, who worked in the Reagan administration's Department of Justice's tax division as an assistant attorney general, wrote that Mrs Palin's per diem payments were considered properly as reimbursements that should not be taxed because the state considered Juneau to be her place of business.

'No special consideration was ever given to Governor Palin, notwithstanding that she was the governor of Alaska,' Mr Olsen wrote in a three-page letter outlining his review of the family's tax returns. -- AP