"That's when his wife said 'no, no, he's been stabbed'.
"He was out to it completely and the way he was sitting, there was blood all over his shirt."
Brian was working with his cousin at a roadblock controlling traffic to the holiday camp and Waihi Beach surf club when the attack happened about 1am.
He ran back to his ute and grabbed a first aid kit. He bandaged the injured man, who was flown by helicopter to Waikato Hospital.
He said hundreds of people were walking around the area at this time of year. There had been several fights, including one involving more than a dozen young men, but the incident had left him and others shaken.
"We had the riots all those years ago and a couple of fights but this is a bit too close to home," he said.
"No-one expects this kind of thing."
The injured man, 64, is an expatriate New Zealander on holiday from Australia with his wife.
Last night, he was in the intensive care unit at Waikato Hospital.
Family members were understood to be travelling to New Zealand last night to be with him.
Police said he and his wife were sleeping in a caravan outside a friend's house.
They got up to investigate a disturbance and the attacker struck.
Waihi Beach, at the western end of the Bay of Plenty, has a population of about 2000, but that number swells during summer as its large stretch of white sandy beach attracts thousands of visitors. .
Western Bay of Plenty mayor Ross Patterson said it was horrific to know the attack had happened at a place popular with hundreds of families during the festive season.
"It's just really disappointing that this has happened, and it's quite stressful to know there's a person out there armed with knives," he said.
Another resident and a friend of the house owners, Clodagh Kendal, said the community was shocked at the incident.
"It's disturbing, I turned the internet on this morning to see how everything went last night to see if there were riots in the Mount or Whangamata and there's a policeman standing at the door.
"They tell me what's happened and that they're looking for a weapon. It's terrible, just awful."
Eastern Waikato area commander Inspector Dana McDonald said the attack happened after the man and his wife were disturbed while sleeping in a caravan at the front of a Waihi Beach Rd property about 1am yesterday.
The couple heard a noise and went to investigate, "and as a result of that the man has received quite a serious injury to his head".
Police are still looking for the weapon used in the attack and are seeking the public's help in identifying the attacker.
"This is not acceptable in any community, it's not acceptable in Waihi Beach, we don't want this sort of behaviour. It's an unprovoked attack to an innocent ... it's absolutely unacceptable behaviour," said Mr McDonald.
