A $200 million state-of-the-art women's and children's hospital is set to open its doors in Melbourne's west in May.

Melbourne's new Joan Kirner Women's and Children's Hospital will open its doors in May, becoming home to more than 150 nurses and midwives.

The $200 million facility at St Albans will house the first neonatal intensive cots in Melbourne's west.

"The new Joan Kirner Women's and Children's Hospital will mean more families in the west can access world-class paediatric and maternity services closer to home," Premier Daniel Andrews said on Thursday.

The hospital aims to take pressure off the nearby Sunshine Hospital, which is forecast to deliver up to 7,000 births each year, by 2026.

It will also include 20 maternity delivery rooms, 237 beds, 39 special care nursery cots, four theatres and additional clinics.

Last month, the Andrews government passed legislation improving nurse and midwife to patient ratios.

Under the laws, the number of nurses and midwives will be rounded up, rather than down, removing a loophole that meant staff often had to carry a workload up to 50 per cent higher than the prescribed ratio.

The move delivers 600 new nurses and midwives in the state's public hospitals and the government says it is working on further strengthening the ratio, resulting in a total of 1,100 new nurses and midwives in the system.

"There's no use building world-class hospitals if our nurses and midwives don't have the resources they need to do what they do best. That's why we've given them the fair patient ratios that they deserve," Health Minister Jenny Mikakos said.