The bodies were discovered by the dead man’s wife at 12.15pm.
She had gone to the apartment to see her three-year-old daughter and seven-month-old boy.
Sentul Police Chief ACP R Munusamy revealed that the body of the father – identified as Cheah Heng Soon – was found on a mattress inside the apartment’s master bedroom.
The children’s bodies were stuffed inside two plastic containers in another bedroom.
“Based on initial checks, police believe the victims had died three days ago,” the portal quoted Munusamy as saying.
The bodies have been sent to the Kuala Lumpur Hospital for a post-mortem.
Police are further questioning Cheah’s 35-year-old wife regarding the deaths, which have been classified as murders.
Cheah and his wife are separated.