Siddaramaiah is in Delhi since Monday.
The Karnataka Pradesh Congress Committee President will leave for Delhi from Kempegowda International Airport here by a 9:50 am flight, his office said in a statement.
The three central observers of the Congress, who interacted with newly elected party MLAs on their choice for chief minister, briefed party chief Mallikarjun Kharge and submitted their report on Monday.
The Congress Legislature Party, which met at a hotel in Bengaluru on Sunday, had passed a unanimous resolution authorising Kharge to pick who will be the next chief minister of Karnataka.
Shivakumar is locked in an intense power struggle with Siddaramaiah over who will lead the government, after the Congress stormed to power by winning 135 seats in the May 10 elections to the 224-member Karnataka Assembly.
Amid speculations about the number of MLAs supporting him and Siddaramaiah for the post, Shivakumar on Monday said his strength is 135, as it was under his leadership, the party won 135 seats.
In just-concluded Assembly elections, the Congress scored an emphatic victory with 135 seats, while the ruling BJP and the former Prime Minister H D Deve Gowda-led Janata Dal (Secular) secured 66 and 19 seats, respectively.