Police are investigating how a 10-month-old baby arrived at Starship Hospital with critical injuries. 

However, Detective Inspector Aaron Proctor, Waitemata Police, has confirmed they believe the injuries were "non-accidental" and were now working to find out what happened. 

Proctor said the baby was presented to Starship on Wednesday evening with critical injuries. 

"Police believe the child's injuries are non-accidental and we are working to establish the circumstances surrounding this." 

Officers have been seen at a Vandeleur Ave, Birkdale, property today. 

A blue tent has been set up out the front, between the two properties. 

Proctor said the child remains in a critical condition in hospital and there have been no arrests at this stage.