"If you live in a palace with 70 rooms, how can you empathise with the poor? I don't understand this mentality," he said, referring to Jagan.
Kiran was addressing a campaign meeting in coastal Andhra in support of Congress candidates for next month's bypolls to one Lok Sabha and 18 Assembly seats.
He alleged the Kadapa MP indulged in corruption by "hiding behind his father (late Y S Rajasekhara Reddy)".
The Chief Minister, who kicked off his campaign in the coastal districts yesterday, alleged that Jagan had ditched Congress and was making false allegations against the party now.
Jagan, who is also YSR Congress President, and Telugu Desam chief N Chandrababu Naidu have been in the thick of campaigning for the by-elections scheduled on June 12.
Bypolls in 16 of the 18 Assembly seats are necessitated due to the disqualification of sitting Congress MLAs who switched loyalty to Jagan, while another sitting member quit in support of the Kadapa MP.
The bypoll in the lone Lok Sabha seat is necessitated due to the resignation of sitting Congress member.