"The important thing is that the lodging rates have been reduced in many locations and some staffing agencies may not be aware of the change," said Joseph C. Smith of TravelTax, a subsidiary of Joseph C. Smith Tax Consultants. "They would be wise to double check the rates of the localities in which they place staff to ensure that they do not over-reimburse their employees."

In the past few years, per diem rates typically increased. Smith said that with the rates going down this year, it could catch some firms off guard.

The per diem rates can be used as an alternative to keeping receipts; however, employers still must do their due diligence to check if employees are away from home overnight on employer business.

Firms may continue to use last year's per diem rates through the end of the calendar year but only if it has been their practice to do so in previous years, Smith said.

To find the new per diem rates, click here.