Former prime minister Atal Bihari Vajpayee, who was on Tuesday admitted to the All India Institute of Medical Sciences after he complained of giddiness, is stable.

"He is stable, conscious, with normal vital signs," AIIMS spokesperson Dr Shakti Gupta told PTI.

Vajpayee, 83, was admitted to a private ward in the Cardio-Thoracic and Neuro-Sciences Centre after he complained of drowsiness and giddiness in the morning.

"He is under observation. We are carrying out various investigations," he said adding, some more tests will be carried out on Wednesday, before the Bharatiya Janata Party leader will be discharged from the hospital.

"A team of doctors, including cardiologist and neurologist, are looking after him," he said.