A head-on collision involving seven motorists left people strewn on Waimarama Rd on Saturday.
The van, believed to be carrying German visitors travelling towards Hastings, and a car collided near the corner of Waimarama and Ocean Beach roads.
Waikau Akonga had just sat down with his wife when they heard the crash at 7.12pm.
She dialled 111 while he comforted injured people lying "all over the place" and said they were soon surrounded by about 100 onlookers as heavy traffic ground to a halt.
"It was hard trying to work out how many were involved or who was in which vehicle, because some got out of one of the vehicles and some were still stuck in the vehicles," Mr Akonga said.
Hastings fire service was the first emergency service to respond.
"We had multiple patients strewn on the road and around the vehicles," incident controller Mike Manning said.
"We also had two males in front of the van which had a high level of entrapment.
"We advised ambulance this was a mass-casualty event and the territory manager mobilised a large fleet of ambulances to come out and assist including the Lowe Corp and Palmerston North rescue helicopters due to the nature of the injuries.
"It was a long and detailed extrication and took us about 45 minutes to free the victims and they were both flown to hospital."
St John Heretaunga territory manager Brendon Hutchinson said three ambulances responded. The two patients flown to Hawke's Bay Hospital had serious injuries and the other five were taken by road to hospital with moderate-to-serious injuries.
A hospital spokesperson yesterday said two have since been discharged and five remained in hospital in a stable condition.
Mr Akonga said he believed speed or overtaking were not contributing factors to the collision.
"I just believe those Germans just thought they were back in their own country and just got on the wrong side of the road."
Mr Manning said fire crews closed the road but were disgusted at the response from intoxicated bystanders.
"There was a high level of intoxication amongst some of the bystanders, to a level that some of these bystanders impeded our operations," he said.
"One highly-intoxicated person got quite animated at us. He needed to get back to Hastings with his family and ended up putting his hands on one of my firefighters.
"We were disgusted with the conduct of some of the intoxicated people there, bystanders, in the way that they obstructed us and impeded our operations.
"It was very disappointing they didn't have enough fortitude to recognised the scene was as highly-charged as it was and we needed to do some rapid work with the extrication and the treatment of the patients who were very unwell."
He said with the coming holiday season people needed to be patient at accident scenes.
"People just need to be mindful that they are not the priority and they should know they can be arrested for obstructing us.
"This was a disappointing aspect of the job, however, what I would say it was an excellent cohesion between fire, ambulance and our sister agency, the rescue helicopters, to bring this scene to a successful conclusion."