Several young men are recovering in hospitals across NSW after being attacked during Australia Day celebrations.

Many people would be expecting a sore head after partying through Australia Day.

But several young men across NSW are recovering in hospital with head injuries far worse than the most savage hangover.

A one-punch assault victim is in a critical but stable condition in Sydney’s Westmead Hospital following an attack in central western NSW.

After being told to leave a house party in Orange, a 20-year-old was followed outside and attacked, his head hitting the road.

The injured man was taken to Orange Base Hospital and later airlifted to Sydney.

The 20-year-old’s assailant was due before Orange Local Court on Monday, charged with recklessly inflicting grievous bodily harm.

Another young man is in hospital with a fractured skull after being beaten outside a pub in nearby Parkes on Sunday night.

The 23-year-old was punched in the stomach and head, then fell over and cracked his skull on the ground.

It’s expected he will also be airlifted to Westmead Hospital for further treatment.

About an hour earlier in Sydney’s east, yet another young man was pushed, punched and smashed his head on the pavement.

The 24-year-old’s head was split open in the unprovoked attack on a busy road at Bondi.

He was taken to St Vincent’s Hospital.

About the same time across town in Rooty Hill, a teenage boy was bashed by a gang.

The 16-year-old was set upon in a park after an argument, punched in the head several times and kicked after falling over.

He was taken to Nepean Hospital with neck and spinal injuries.

Again, the group had disappeared before emergency services arrived.

Police said most party-goers across NSW were well behaved and only about 100 were arrested during an antisocial behaviour blitz.

More than 2000 police were on patrol, and during their operation charged 100 people with 127 offences including assault, affray, assault/hinder police, offensive behaviour, breach of bail and drink-driving.

Of the 30,000 in attendance at the Big Day Out, more than 570 were searched and 122 charged.

Seventy one were charged with drug possession and two for drug supply, while 25 people were issued with cannabis cautions and three were charged for offensive behaviour.

Police seized alcohol from 10 under-aged youths.

NSW Premier Barry O’Farrell last week announced tough new measures to tackle alcohol-fuelled violence including an eight-year mandatory minimum sentence for “one-punch” assaults that result in death and involve alcohol or drugs.