A man will face court following a fatal crash on the NSW south coast earlier this week.

Emergency services were called to Bolong Road at Bolong, just before 12.30pm on Thursday, after two cars collided.

A 79-year-old man died at the scene and his 72-year-old wife was airlifted to St George Hospital, but died on Saturday.

A two-year-old boy who was a passenger in the second car remains in Wollongong Hospital in a serious condition.

A 35-year-old man was arrested at Wollongong Hospital on Monday, police say.

He was taken to Wollongong Police Station and charged with two counts of dangerous driving occasioning death and dangerous driving occasioning grievous bodily harm.

He was refused bail to appear at Wollongong Local Court on Wednesday.

AAP