Mr Banharn celebrates his 82nd birthday today.
Mr Banharn said he has been in poor health with inflammation in the lungs and had to go to the hospital three or four times a month. His weight has dropped from 64 to 57kg, he said.
He said he has not followed up political developments because he has to take care of his health.
"It is not now the time for us to get involved in politics. We can only let those in charge do their work," Mr Banharn said.