A sittting MP from Gusii confirms that ex-presidential candidate Simon Nyachae was flown to undisclosed hospital in South Africa for specialised treatment.
The octogenarian politician was admitted in Nairobi Hospital in ICU last week after reportedly collapsing in his house.
But the situation may have deteriorated, forcing the family to seek specialised treatment in Johannesburg.
"The situation diminished and they had to jet him out on a chartered plane," said the MP, who sought anonymity.
He added: " I am told that he is suffering from chest pains which have since turned severe."
At 86, Nyachae is on retirement since 2008 after losing his Nyaribari Chache seat to Robert Monda.
For years, the former powerful finance minister controlled Gusii politics. He would contest presidency in 2002 where he emerged third.
Details about the hospital which he was admitted remains scanty.