The 19-year-old man and 18-year-old woman were camping near a skatepark at the intersection of McAllister and Beach streets when they were attacked early yesterday morning after being woken in their tent.
The couple managed to escape to a nearby house for help and another person who heard screams also contacted police.
Police officers were quickly on the scene and the group of alleged offenders, who had been ransacking the tent, fled.
A police dog and handler tracked two of the alleged offenders making two arrests. Police made a further two arrests a short time later. A fifth person, believed to be a male teenager, is still wanted by police.
Both tourists were taken to Whakatane Hospital. The woman suffered facial and arm injuries including fractures and the man suffered bruising, lacerations and has lost some teeth.
Officers have recovered items believed to have been used as weapons but won't say what they were.
Some personal property belonging to the couple is still missing and police are asking anyone in the vicinity of the skatepark and river to keep an eye out for any items linked to the incident.
"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," Area Commander Inspector Sandra Venables said. "I must acknowledge both the members of the public who came to their aid and also the officers whose swift actions resulted in a number of early arrests."
Police say they have been overwhelmed by calls with offers of accommodation and donations for the couple. Anyone with information should contact Whakatane police on (07) 308 5255, or Crimestoppers, anonymously, on 0800 555111.
additional reporting Jamie Morton