Vidya Charan Shukla, a veteran leader of India's ruling Congress party who was critically injured in a Maoist attack last month, has died.

The 84-year-old politician sustained three bullets in his body after he was caught in the middle of the rebel ambush on a convoy of party leaders in the central state of Chhattisgarh on May 25.

He was airlifted to the Medanta Medicity Hospital in Gurgaon on the outskirts of New Delhi and operated for intestinal and liver injuries.

"Unfortunately, despite all efforts by a team of specialists, he succumbed to his injuries and illness and passed away today afternoon," a statement issued by the hospital said on Tuesday.

Shukla joined former Prime Minister Indira Gandhi's cabinet in 1966 and went on to become the country's foreign affairs, defence and home affairs minister in later years.

At least 24 people including the Congress Party's Chhattisgarh chief Nand Kumar Patel and Mahendra Karma, another local party leader, were killed in the attack, the biggest staged by Maoists in three years.

More than a third of the India’s 626 administrative districts are affected by the left-wing insurgency, which the Indian prime minister has described as the main internal security threat facing the country.