Wellington Police have revealed further details of serious injuries sustained by a young Hutt Valley baby

Family took the three-month-old to hospital just under a month ago.

Detective Senior Sergeant Steve Wescott says the baby had nine fractures, including across her ribcage - and ankle and upper arm fractures.

He doesn't believe they were accidental - and says they happened on separate occasions.

The baby's condition is improving.

Anyone with information is asked to come forward.