Voting will be held for 16 Rajya Sabha seats spread across Maharashtra, Karnataka, Rajasthan and Haryana on Friday.
A total of 57 Rajya Sabha seats, spread across 15 states, had fallen vacant recently. Among these, candidates had been declared elected unopposed in 41 seats.
Voting will be held in the respective state legislatures in Maharashtra (six seats), Karnataka (4 seats), Rajasthan (4 seats) and Haryana (2) seats. Notable candidates include Union Ministers Piyush Goyal (contesting from Maharashtra) and Nirmala Sitharaman (Karnataka).
Given the relatively narrow difference in number of legislators of opposition and governments in these four states, political parties and their allies have scurried to 'secure' their MLAs to minimise the chances of cross-voting.
In Rajasthan, authorities suspended internet services in the Amer area of Jaipur, where Congress MLAs are staying.
The move has been attributed to the government's worries about poaching of MLAs.
The Congress MLAs reached Jaipur from Udaipur on Thursday and were staying at the Hotel Leela in Amer.
The Congress hopes to win three seats in Rajasthan. But with 108 MLAs, the Congress is 15 legislators short of the numbers to win all three.
In Maharashtra, the AIMIM has pledged the support of its two MLAs to the ruling MVA coalition. "Piyush Goyal, Anil Bonde, Dhananjay Mahadik (BJP), Praful Patel (NCP), Sanjay Raut and Sanjay Pawar (Shiv Sena) and Imran Pratapgarhi (Congress) are in the fray for the six seats of Rajya Sabha," Hindustan Times reported.