A 17-year-old boy has died after he was punched on his way home from a fast food outlet in Melbourne's outer-south east.

The boy was walking home with family and friends from Hungry Jack's in Pakenham just after 12am (AEDT) yesterday when there was a confrontation with a large group of youths in Cunningham Crescent.

After a verbal exchange, the 17-year-old boy was punched and fell, hitting his head on the road, police said.

After being helped home following the assault, he was later airlifted to The Alfred hospital, where he died about 1.30pm today.

Police said in a statement a 17-year-old boy had come to a police station today afternoon and was assisting police with their inquiries into the incident.