A neighbour heard screams and phoned police, who arrived as the group were ransacking the tent. Two offenders were caught after being tracked with a police dog to a nearby river, while two others were arrested a short time later nearby.
Police said two male adults and two juveniles, a male and female, were being spoken to, while a fifth suspect, believed to be a male juvenile, was still being sought.
Yesterday, the park was cordoned off as police searched a riverbank, recovering items believed to have been used as weapons.
The passenger door of the victims' vehicle remained open, with contents spilled on the ground, and belongings scattered about the entrance of their tent.
The victims were yesterday recovering in Whakatane Hospital and have declined to give interviews. Some personal property belonging to the couple was still missing, and their families back in Europe had been notified of the attack.
Neighbours who spoke to the Herald expressed their dismay at the incident, and said there had been no concerns around safety in the park.
Whakatane Mayor Tony Bonne said his town was "as safe as any other place around New Zealand" and the spot the tourists chose to camp at was "not a bad area".
"We don't like it, we don't accept it, and particularly in our area where we really welcome tourists to come in and see the beauty of the Eastern Bay, we don't need that publicity at all."
Inspector Sandra Venables, the Eastern Bay of Plenty area commander, expressed disgust at the attack.
"This is an appalling and mindless attack on a young couple and incredibly sad that this will be their lasting memory of Christmas in our beautiful country."
The police station had been inundated with phone calls from across the country offering donations and accommodation for the couple.
They included an offer of a free stay at the Murupara Motor Camp, while another person who reached out through the Herald offered $1,000 and a stay at Pauanui Beach.
Mr Bonne said his community was rallying around the pair.
"The love of the community goes out to the couple, and from the injuries that they've got, it's just unbelievable, it's uncalled for."