Construction began last week on the $4.8million Southern Health pregnancy assessment unit at Clayton.

The unit will improve care for expectant mothers, free up hospital beds and enable about 260 more births a year at the hospital.

Monash Medical Centre obstetrics director, Professor Euan Wallace said the unit was expected to be completed next year and would specialise in the care of women suffering late-stage pregnancy complications.

Health Minister Daniel Andrews said it would ensure pregnant women were given the safest and highest-quality maternity care available.

"The pregnancy assessment unit will be an eight to

10-bed multi-disciplinary facility where antenatal monitoring and tests can be undertaken on a same-day basis, improving the care for the mothers-to-be and helping them in the best ways possible."

Mr Andrews said the unit would care for some patients who would otherwise go to the emergency department and would also make more beds available in the hospital's birthing suite.

Southern Health delivered 8412 babies and catered for more than 150 mums and families a week in the past financial year.