Finance Minister Brian Lenihan has confirmed he will undergo treatment to remove cancerous tissue in his pancreas.
While beginning a course of chemotherapy and radiotherapy this week, he has also vowed to remain in office and implement the Government's economic recovery plan.
Disclosing details for the first time of his illness, Mr Lenihan said a blockage at the entrance to his pancreas was identified during the week before Christmas.
Although his condition is serious, the diagnosis is not as stark as full-blown pancreatic cancer which he was reported to have last week, according to a Government source.
"A stent was inserted and the pancreas is now functioning normally," he said.
"Cancerous tissue has been identified in the material that has caused the blockage. My medical advice is that chemotherapeutic and radiotherapeutic treatment are required."
Mr Lenihan said his doctors have advised he is fit to continue in his role as Finance Minister during one of the worst economic crashes in recent memory.
"If that position were to change in the course of my treatment, I would be the first to recognise it," he added.
"At all times, I will act in the best interests of the country and in accordance with any medical advice received."
During the week before Christmas, I underwent tests in hospital which identified a blockage at the entrance to my pancreas. A stent was inserted and the pancreas is now functioning normally. Cancerous tissue has been identified in the material that has caused the blockage. My medical advice is that chemotherapeutic and radiotherapeutic treatment are required. I will begin the treatment later this week.