Besides the prime minister, other Bharatiya Janata Party leaders who have proposed her name include Home Minister Rajnath Singh and External Affairs Minister Sushma Swaraj, Parliamentary Affairs Minister Venkaiah Naidu said.
The formal election of the new speaker will take place Friday.
Mahajan, 72, is an eight-term member of the Lok Sabha from Indore, Madhya Pradesh.
Representing Indore in the Lok Sabha since 1989, she was a minister of state in the Atal Bihari Vajpayee government from 1999 to 2004.
Mahajan was elected from Indore for the eighth time in the 2014 general election by a margin of 4.67 lakh votes.
