Claiming that "as per my earlier directive, BSP workers will vote for a candidate who will be in a position to defeat the BJP" Ms Mayawati said "there is nothing wrong in it".
Earlier in the day, BSP's Gorakhpur zone coordinator Ghanshyam Kharwar had declared his party's support to the Samajwadi candidates on both the seats.
"Barring Karnataka, there is no electoral tie-up of the BSP with any political party. In Uttar Pradesh, whenever there will be an electoral alliance of the BSP with SP or any other party, it will not be done stealthily but will be made public," Ms Mayawati said.
Bypolls to the Gorakhpur and Phulpur Lok Sabha seats will be held on March 11. The results will be declared on March 14.
Mr Adityanath, who held the Gorakhpur Lok Sabha seat for five straight terms, has been aggressively campaigning for the BJP's Upendra Dutt Shukla.
Mr Maurya was a first-time Lok Sabha member from Phulpur, a seat the BJP won for the first time in 2014, riding the "Modi wave". The constituency was once held by former Prime Minister Jawaharlal Nehru.
Ms Mayawati admitted to an arrangement of "vote transfer" between BSP and SP lawmakers for the upcoming polls to the Rajya Sabha and the Uttar Pradesh legislative council but refused to call it an "electoral alliance". Polling for 58 Rajya Sabha seats, including 10 from Uttar Pradesh, will be held on March 23.
"BSP on its own cannot send anyone to the Rajya Sabha. The SP too does not have the numbers to send two lawmakers to the Rajya Sabha. To ensure the victory of its second candidate, it will need additional votes. Our party after holding deliberations with the SP has decided that our candidate will go to the Rajya Sabha. In return, we will help them in the legislative council elections," the BSP chief said.
Polling for 58 Rajya Sabha seats, including 10 from Uttar Pradesh, will be held on March 23.
Mr Adityanath, who vacated the Gorakhpur Lok Sabha seat last year, took a swipe at the BSP and SP. "You can guess that those memorials in Lucknow that were made in the name of great Indian leaders, who was threatening to destroy them? You can guess who is who."