New Zealand Ambassador to the United States and former Prime Minister Mike Moore is in a Washington hospital having fallen ill earlier this week.
The Herald understands he has had a mild stroke.
Mr Moore has had other health problems and had a heart valve operation a year ago.
He has been in the diplomatic post in the US capital city since 2010 and even without ill-health, he and his wife, Yvonne, had been widely expected to return home thisyear.
Foreign Minister Murray McCully would not confirm whether he had suffered a stroke but a spokesman said: "I am aware that Ambassador Moore is unwell. Out of respect for his privacy, I won't be providing further comment at this time."