Christchurch police have arrested four of five people sought in relation to a vicious assault on a group of tourists in the central city on the weekend.

Eight English and Danish tourists - two women and six men - were walking in Cashel Street about 1am on Saturday when they were attacked from behind by a group of men.

Two of the tourists were stabbed, one suffered a broken wrist and others minor concussion and bruising.

Four were treated in hospital.

Detective Senior Sergeant David Harvey said tonight four Christchurch men, all aged 22, would appear in Christchurch District Court tomorrow facing assault and assault with intent to injure charges.

He said they were following an active line of inquiry for the fifth man alleged responsible for the stabbing.