Man arrested over horror crash that killed mum

A 39-year-old man has been arrested after a horror crash on the New South Wales south coast that claimed the life of a woman, and left her husband and son fighting for life.

Christopher Sharp was allegedly behind the wheel of a Volvo that swerved into oncoming traffic on Matron Porter Drive in Milton, 220km south of Sydney, on Thursday afternoon.

The Volvo ploughed into a Subaru carrying the Mobarrez family, who were returning to Sydney after attending a swimming meet at nearby Mollymook.

Tamara Mobarrez, 36, was killed in the crash. Her husband, former Olympic swimmer Hamid Mobarrez, and their five-year-old son, Eli, were critically injured and remain in hospital.

Mr Mobarrez is head swimming coach at Sydney's Kincoppal School in Rose Bay, where his wife also worked in administration.

He is now in a stable condition at St George Hospital while his son is in the care of staff at the Royal Children's Hospital in Randwick.

Christopher Sharp was discharged from hospital this morning and taken directly to Kogarah Police Station, where he was questioned by officers from the Crash Investigation Unit for several hours.

He has been charged with several offences, including dangerous driving occasioning death.

Sharp was granted bail and is expected to appear in Sutherland Local Court on February 20.