Rahul, Priyanka and Sonia Gandhi offered to resign after elections but Congress shot down the suggestion.
A Congress spokesperson has been sacked in Tamil Nadu after he suggested that Rahul Gandhi and Priyanka Gandhi Vadra should step aside to "save the Congress".
Americai V Narayanan, a member of the All India Congress Committee (AICC), also said the party's alums like Mamata Banerjee, Jagan Mohan Reddy and K Chandrasekhara Rao should return and restore people's confidence in the Congress.
"To build the confidence of the people of India, bring in ex Congress leaders who have proven track record – like Mamata Banerjee, Jagan Mohan Reddy, Sharad Pawar, K Chandrasekhara Rao (KCR) - and request them to merge their party with the Congress," Mr Narayanan told NDTV.
"This will provide confidence among outsiders and allies that the Congress will emerge. Once the perception comes, power comes and money comes (sic). If Mamata Banerjee returns, she will convince the others," he said.
Mr Narayanan is a rare party leader from the south to go public against the Gandhis' leadership. He is not a part of the "G-23" or 23 dissenters who wrote to Sonia Gandhi two years ago asking for an organisational revamp and a full-time and visible leadership.
Asked why he believed Mamata Banerjee could consider merging her Trinamool Congress with the Congress when she has established herself as a Chief Minister and is now aspiring to become the Prime Minister, Mr Narayanan said she has "better odds of becoming Prime Minister being in the Congress rather than the Trinamool".
On what he thought the Gandhis should do, Mr Narayanan said, without mincing words, that Sonia Gandhi should be at the forefront and her children should step aside.
"I love Rahul Gandhi but unfortunately, he has not delivered. Sonia Gandhi has a track record of delivery. I request Sonia Gandhi to be one among equals in the decision-making body and I request Rahul and Priyanka Gandhi to stay aside (sic)," the Tamil Nadu Congress leader said.
The Congress lost Punjab and failed in its attempt to make a comeback in Goa, Uttarakhand and Manipur in the elections held recently. The latest debacle revived calls from the "G-23" dissenters for a leadership overhaul.
During a post-mortem of the drubbing, Sonia Gandhi offered to resign, along with Rahul Gandhi and Priyanka Gandhi Vadra, but the suggestion was shot down by the party.
This morning, Sonia Gandhi appeared to send out a message to the rebels as she told party MPs on the election results: "Our dedication and determination, our spirit of resilience is under severe test. Unity at all levels of our vast organisation is of paramount importance and speaking for myself, I am determined to do whatever is needed to ensure it."