CANBERRA -- As the Australians across the country celebrated their national day on Sunday, the Australian Day holiday was tainted by a number of violent attacks, especially in the state of News South Wales.

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, the 20-year-old was followed outside and attacked, his head hitting the road.

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.

Also on Sunday night 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, a famous beach near Sydney.

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.

The group had disappeared before emergency services arrived.

Police said that about 100 were arrested during an antisocial behavior blitz in NSW.

Under the so-called Operation Shoreline, more than 2,000 officers were deployed across NSW on Sunday, targeting anti-social behavior and alcohol-related crime as people celebrated the Australia Day.

During the operation, 100 people were arrested and charged with a total of 127 offenses including assault, affray, assault/hinder police, offensive behavior, breach bail and drink-driving, police said.

"The small number of people that chose to do the wrong thing were targeted and swiftly dealt with by police," said Operation Shoreline Commander Assistant Commissioner Mark Murdoch in a statement.

Murdoch said excessive alcohol consumption was again of concern and he urged those continuing celebrations on Monday to do so responsibly and stay safe.

In addition to this, a separate police operation was conducted at Sydney Olympic Park, where more than 30,000 music fans attended the Big Day Out festival.

Drug-detection dogs conducted more than 570 searches of people and police arrested and charged 122 revelers.

Hundreds of people were also refused entry or ejected from the venue for inappropriate and anti-social behavior, police said.