New Delhi/Bengaluru,  (PTI) All eyes are now riveted on the Congress' central leadership that will pick the new Karnataka chief minister, a decision preceded by intensive consultations, one-on-one interaction with MLAs and even a 'secret ballot'.

After the Congress party's stupendous victory in the May 10 assembly polls, intense lobbying for the chief minister's post in Karnataka started for former chief minister Siddaramaiah and KPCC president D K Shivakumar.

The party faces the uphill task of satisfying the two camps and is working on a 'formula'.

Both the top Karnataka leaders have been called to Delhi by the party high command for further consultations on government formation in the state. While Siddaramaiah has left Bengaluru and will be in the national capital by Monday evening, Shivakumar is likely to follow him later in the night.

The three central observers deputed by the Congress returned to the national capital on Monday after speaking individually to the newly elected MLAs.

The observers are putting together the views expressed by all the newly elected MLAs and will hand over the report to party president Mallikarjun Kharge by late Monday night, sources told PTI.

Senior party leader B K Hariprasad said the MLAs were asked for their open feedback on their choice of chief minister during their interaction with the observers and also a secret ballot was held for the CM's name. The observers have brought the ballot boxes to Delhi along with them.

Kharge is likely to take a decision on who will be the next chief minister of Karnataka soon. He is also likely to hold consultations with top Congress leadership, including Sonia Gandhi and Rahul Gandhi, before arriving at a decision.

Meanwhile, the party is also gearing up for preparations for making the swearing-in ceremony of the chief minister a big show of strength, where several opposition leaders will be invited.

Supporters of both Siddaramaiah and Shivakumar had raised slogans projecting them as the next chief minister outside the meeting of the Congress Legislature Party on Sunday evening.

The CLP had passed a resolution authorising the party chief to pick the chief minister.

A poster war by supporters of both leaders also erupted soon after the party won the election.

Kharge had appointed former Maharashtra chief minister Sushilkumar Shinde, party general secretary Jitendra Singh and former AICC general secretary Deepak Babaria as observers for the election of the CLP Leader of Karnataka.

The three leaders along with AICC general secretary in-charge of Karnataka Randeep Surjewala arrived in Delhi from Bengaluru and will meet Kharge later in the evening.

The observers spoke individually to all the newly elected MLAs after dinner at a private hotel on Sunday night and completed the process late at night.

While Siddaramaiah is a leader with mass appeal, is popular among all sections and has the experience of running a government of full five-year term from 2013-18, Shivakumar has strong organisational capabilities, is considered resourceful and Congress' troubleshooter during tough times and has the backing of the dominant Vokkaliga community, its influential seers and leaders.