"I do not agree with this 75-year age bar for appointment of a person as minister," Sinha, second term BJP Lok Sabha MP from Patna Sahib, said.
67-year-old Sinha, who served as Union minister in the NDA government of Atal Bihari Vajpayee, disputed fixing such an age bar.
"Instead of age, the criteria shall be mental alertness and health," he said.
"Even at an age of 86, veteran BJP leader L K Advani has a sharp memory and energy like a 40-year-old man," said Sinha, who has on numerous occasion described Advani as his "political guru".
"Who can question the mental alertness and physical activities of Advani or Murli Manohar Joshi" he asked, adding that for successfully running the government maturity and rich experience of members are also required.
"There are people who are dull and lethargic at a young age of 50," Sinha who has been BJP's star campaigner for long said in support of his argument.
The "Bihari Babu" said it was a well known fact that for an average person the political career starts at 50.
"To curtail the political career at the age of 75 means one has only a span of 25 year in politics," he said.
Sinha, who won from Patna Sahib by over 2.65 lakh votes this time defeating his nearest Congress rival Kunal Singh, a Bhojpuri actor, was rated high as a probable in Modi's team.
Ravishankar Prasad, Radha Mohan Singh, Ram Vilas Paswan and Upendra Kushwaha from Bihar found place in the new Cabinet sworn in on May 26.