Bihar Grand Alliance consisting of the RJD, Congress, HAM, RLSP and VIP was formed in Bihar ahead of the Lok Sabha elections.
Mayawati's announcement came a day after she held a meeting with party workers to review the BSP's performance in the recent Lok Sabha polls.
'If Nitish Kumar joins the Grand Alliance again, we have no objection to it,' Rabri Devi told media on Monday night.
Mayawati said her party had not benefited from the alliance with the Samajwadi Party.
Upon being asked, why no leader of state Congress party attended the alliance’s post-poll debacle review meeting, Tejashawi Yadav said he was in regular contact with Congress president Rahul Gandhi.
The RLSP is led by former union HRD minister Upendra Kushwaha, who has lost the polls from both Karakat and Ujiyarpur LS constituencies.
"The 'Mahathagbandhan' will never be voted 'in' by the people of India because they will always keep politics above them," Supriyo tweeted.
The Mahagathbandhan leaders also targeted the Congress, alleging that it is "anti-Dalit" like the BJP and wants the people to remain poor.
Would rather die than help BJP: Priyanka clarifies; Akhilesh terms it 'excuse', Mayawati smells collusion
Priyanka Gandhi's claim to have fielded weak candidates to eat into BJP’s vote share in UP has not cut any ice with Gathbandhan leaders Akhilesh Yadav or Mayawati.
This social engineering will be an acid test for the NDA in all the 40 Lok Sabha seats against the Grand Alliance of the RJD, Congress, Hindustani Awam Morcha and the Rashtriya Lok Samata Party.
As UP heads into the first phase of the Lok Sabha elections, the large population of Muslims in its western belt is an indecisive lot, torn between the traditional pattern and an eye on the future.
Congress has been allocated nine seats in Bihar, followed by one for CPI(M), five for Upendra Kushwaha's RLSP and three each for Jitan Ram Manjhi's HAM and Mukesh Sahni's VIP.
Former test cricketer Kirti Azad, who joined the Congress recently, said he would request the party leadership to take 'decisive' measures.
The four-phase Lok Sabha polling will begin on April 29 in the state.
While the RJD has announced the names of the two candidates, the Congress is likely to make an announcement by Sunday evening.