Mamata, who arrived here last night, will meet both leaders later in the day.
"Today I will meet Soniaji, Manmohan Singhji and and invite them to attend the swearing-in ceremony. Then I will leave (for Kolkata)," she told reporters.
However, she parried questions whether other issues would figure during her meetings with Sonia and Singh.
Sources, however, said the issues of government formation in West Bengal and Banerjee's successor in the Railway Ministry are expected to come for discussion.
The sources said Mamata would also gift the leaders with special Kolkata sweets to celebrate the victory.
The Trinamool Congress-Congress combine stormed to power on Friday, ending 34 years of Left Front rule in West Bengal.