The Ministerio de Hacienda said Monday that the minster, Edgar Ayales, would soon undergo surgery.
A vice minister, José Luis Araya, will hold the job until the minister returns.
The exact nature of the medical problem was not disclosed. Nor did the ministry say where the procedure would take place.
Ayales is schedule to return Jan. 6.
He is the Chinchilla administration point man for tax reform and recently completed what was called the national dialogue in which public comment was sought on the financial crisis facing the country due to unbridled spending.
Ayales is expected to unveil a number of new taxes that the administration will submit to the legislature. Among these is a proposed value added tax.