PV Narasimha Rao assumed office in June 1991 and stayed in power till May 1996.
The Congress sidelined PV Narasimha Rao to keep the focus on the Nehru-Gandhi family, said his grandson on Friday and demanded an apology from Sonia Gandhi and Rahul Gandhi for ignoring the former prime minister.
Narasimha Rao's grandson, NV Subhash, who is now affiliated to the BJP, claimed that Congress leaders did not pay respects to the former prime minister on his birth anniversary today.
"After the Congress's 1996 debacle, he (Mr Rao) was sidelined due to many issues, which were not concerned with his government policies. The Congress party thought that if anyone apart from Gandhi-Nehru family continues then they themselves will not be noticed and so he was sidelined," Mr Subhash told ANI.
"All failures of the Congress party have been attributed to PV Narasimha Rao and his contributions have not been credited to him. I demand that Sonia Gandhi and Rahul Gandhi should apologise, and come and pay their tributes to him," he lashed out at the Congress.
Mr Subhash had joined the BJP in 2014 and is one of the official spokespersons of the party's Telangana unit.
He alleged that even on his grandfather's 98th birth anniversary, the Telangana Congress leaders did not pay their obeisance to the former prime minister.
"None of the Congress leaders from Telangana have come and paid floral tributes to him. Everyone, including BJP, TRS and TDP came and paid their respects but not Congress. This shows how autocratic they are," Mr Subhash said.
He outlined his grandfather's contribution to the country and credited him for taking steps to lift the country from economic chaos.
"His contributions to Congress and the nation has been appreciated by everyone all over the world. When Narasimha Rao took over in 1991 after Rajiv Gandhi''s death, he contributed with the help of Manmohan Singh as finance minister. It (Our country) was in doldrums. His contributions is immense which cannot be measured," he said.
Mr Subhash also praised Prime Minister Narendra Modi for mentioning Narasimha Rao's name in the Lok Sabha.
"While addressing in the Lok Sabha, Prime Minister Narendra Modi praised Narasimha Rao because of his contributions made in the country and due to the economic policy implemented in 1991. With that economic policy, following governments did not deviate from it and now we see fruits of that economic policy," he said.
On Tuesday, PM Modi took a potshot at Congress, saying that the party never recognised the efforts of former prime ministers like Narasimha Rao, Atal Bihari Vajpayee and Manmohan Singh.
"Did those in power from 2004 to 2014 ever talk about the good work of Atal ji? Did they ever speak about the good work of Narasimha Rao ji? In this Lok Sabha debate, the same people did not even speak of Manmohan Singh ji," he said while replying to the motion of thanks to the President''s address in Lok Sabha.
Earlier in the day, PM Modi paid tribute to Mr Rao and called him a "veteran administrator" who "led the nation at a crucial juncture of our history."
PM Modi also applauded the former prime minister for his leadership and for taking steps which contributed to the progress of the nation.
"Remembering Shri PV Narasimha Rao Ji on his birth anniversary. A great scholar and veteran administrator, he led the nation at a crucial juncture of our history. He will be remembered for taking pioneering steps that contributed to national progress," the Prime Minister tweeted.
Narasimha Rao, the ninth prime minister of India, assumed office in June 1991 and stayed in power till May 1996. He is credited with bringing many economic reforms in the country particularly for dismantling the "License Raj" in the country.
It was during his term that he appointed Manmohan Singh as finance minister, who ushered in a series of economic reforms to lift the country from a worsening economic crisis.
Narasimha Rao's five-year tenure also saw the demolition of the Babri Mosque in Uttar Pradesh's Ayodhya in 1992.
Mr Rao, a six-time lawmaker, died at 83 in 2004.