Targeting Prime Minister Narendra Modi, Patel said when the Congress decided to postpone its rally, earlier scheduled for February 28, following the terror attack in Pulwama last month, the PM was busy addressing gatherings across the country.
Mayawati said that in case of a tie-up with the Congress in the past, the party did not benefit.
The Congress leaders are among those invited by the prime minister to the ceremony.
Besides Rahul and Sonia Gandhi, former prime minister Manmohan Singh and the CWC members also paid tributes to Mahatma Gandhi at the Bapu Kuti.
Though there was no official word from both the parties, the sources claimed that two Uttar Pradesh-based political outfits will contest 37 Lok Sabha seats each.
Telugu Desam Party chief and Andhra Pradesh Chief Minister N Chandrababu Naidu is coordinating the meeting. He has invited the leaders of all the non-BJP parties.
All India Congress Committee general secretary in-charge of Uttar Pradesh Ghulam Nabi Azad said the party would not react immediately and would come out with a detailed reaction in Lucknow on Sunday.
Modi, 68, was administered the oath of office and secrecy by President Ram Nath Kovind at a glittering ceremony at the forecourt of majestic Rashtraparti Bhavan.
Many BJP leaders are of the view that most key members of the previous Cabinet could be retained.
Over 20 political parties, except the Biju Janata Dal and the Communist Party of India-Marxist-led Left Front, took part in the massive rally.