Indian Prime Minister Manmohan Singh has endorsed Rahul Gandhi to lead the ruling Congress party, saying he would be "happy" to work under the scion of the Nehru-Gandhi dynasty, reports said Sunday.

Singh, who will turn 81 later this month, made the comment to reporters late Saturday while flying back from Russia after attending the G20 summit in St Petersburg.

"I would be happy to work for the Congress under the leadership of Rahul Gandhi," the Hindustan Times newspaper quoted the prime minister as saying.

Singh said 43-year-old Gandhi "would be an ideal choice for prime minister after the 2014 elections".

The calls for Gandhi -- whose father, grandmother and great-grandfather were prime ministers -- to embrace what many Congress supporters say is his political destiny come despite the party's poor showings in state elections last year.

Gandhi's mother, Sonia, has long been seen as grooming him to succeed Singh as prime minister of the Congress-led national government.

But his appetite for India's turbulent political scene has often been called into question due to his refusal to accept repeated requests to take on ministerial responsibilities.

The main opposition Bharatiya Janata Party (BJP) is yet to name a candidate for the election but hardline Hindu nationalist Narendra Modi has emerged as favourite since winning key state polls last year.