"Bal Thackeray is not on ventilator, but is on continuous oxygen," his close source said on Tuesday.
He said the 86-yea-old Sena patriarch, who has been suffering from breathing problems, continues to be under medical supervision.
"His health is not so good. He is not eating anything," he said.
A number of leaders including former President Pratibha Patil have visited Thackeray's residence 'Matoshree' over the past few days to enquire about his health.
Thackeray has been unwell for some time. Last month, he could not attend his party's annual Dussehra rally, but addressed it through a video recorded message.