The Vagabond Backpackers owner, who asked not to be named, said the "saddening" incident occurred as the pair were putting a friend into a taxi after a goodbye get-together.
He did not see the fight but understood the tourists were assaulted by a group walking past the hostel from town possibly "looking for trouble", he said.
"It's just something that's exceedingly rare in New Zealand, just random bad luck. Fifteen years I've had the hostel and we've never had a problem like this, nobody's ever been mugged or anything.
"It also doesn't even matter if it's tourists, if it was Kiwis the same thing happened to it's not nice either. But these people are guests in our country, this is their home while they're away - you just want them to have a nice, safe, secure stay."
He said one employee heard the incident and called the ambulance.
It had been an "extreme worry" for the hotel staff, management and guests who were all glad to know the tourists were in a stable condition today, he said.
"We're a centrally located hostel, and probably like every other centrally located hostel in New Zealand, there's going to be silly people walking around at 3 in the morning sometimes and thankfully most of them just carry on their way bumbling home.
"It's just very sad and shocking," he said.
It is the second time this year tourists have been hospitalised after an "unprovoked" attack.
In January, two American tourists were attacked in Paihia outside the Bay Adventurer Backpackers.
The incident shares similarities with the Christchurch attack - with both occurring between 2.30am and 3am on Saturday mornings outside hostel accommodation.
A German tourist was also hospitalised after receiving serious injuries in an assault while he was camping in the Waipu area in November last year.
Police are still hunting for the group who assaulted the two tourists in Christchurch and witnesses have been asked to contact Detective Marc Boodee on 03 363 7400.
