Although Lee has receded from the public and political scene, his health is watched closely as he is still seen as an influential figure for the current government, headed by his oldest son.
He has remained a prominent presence at home and abroad after resigning in 1990 to take up the advisory posts of senior minister and then minister mentor, which he held until his retirement from the cabinet in 2011.
His pro-business and strict law-and-order policies are credited for transforming Singapore into a finance and wealth management centre, one of the world's busiest ports, a high-technology hub and a clean, green and safe place to live.