He was taken to Southland Hospital where he had surgery, a police spokeswoman said.
"He is expected to recover in time. We wish him well.
"Police would like to thank the public who helped this man before police arrived."
The spokeswoman said both dogs had been located last night, and were now with the council.
She said the outcome for the dogs was in the hands of the council, along with whether their owners would be charged.
"Inquiries into the attack are ongoing and we continue to talk to the owners of the dogs, who are upset by what's happened."
Bruce Halligan from Southland District Council said they were treating the attack as serious.
"We currently have both dogs impounded in our pound facility here and what we do with any of these sorts of situations is that we run a formal investigation process.
"We are in the process of gathering that information at the moment, so at this point in time I cannot give you any definitive information as to what the likely outcome of the process will be.
"But it was certainly a serious attack and we are treating it accordingly."
Halligan hoped they should have an outcome by the end of the week.
"The sorts of things that are relevant are establishing the facts of the situation in terms of exactly what happened, and also the attitude of the dog owners - all those things are taken into account when we are assessing the appropriate enforcement action.
"We have real sympathy for the victim and are hoping that he has a speedy recovery."
Rottweilers are currently not classified within New Zealand's menacing and dangerous dogs list; which includes American pit bull terriers, Brazilian fila, Japanese tosa, dogo argentino and perro de presa canario.
Under the Dog Control Act 1996 a person may, for the purpose of stopping an attack, seize or destroy a dog if a person is attacked by the dog; or a person witnesses the dog attacking any other person, or any stock, poultry, domestic animal, or protected wildlife.
The owner of a dog that makes an attack, commits an offence and is liable on conviction to a fine not exceeding $3000 - in addition to any liability that he or she may incur for any damage caused by the attack.
If the court is satisfied that the dog has committed an attack and that the dog has not been destroyed, the court must make an order for the destruction of the dog unless it is satisfied that the circumstances of the offence were exceptional and do not warrant destruction of the dog.
Witnesses stop vicious attack
Beaumont was rescued by a brave neighbour and an off-duty police officer.
Neighbour Annie Burazor said she was alerted to the attack by her stepdaughter.
She grabbed a 50cm knife-sharpening steel as she rushed outside, to be confronted by the harrowing sight of the dogs mauling Beaumont on his face, arms and legs.
Burazor, who works with special needs students at Ruru Specialist School in Invercargill, said the young man was "completely covered in blood" but Beaumont, who has autism, was not screaming.
"He doesn't react the same as other people would. There was no loud screaming."
While she prevented them mauling Beaumont for brief periods, she was unable to drive the dogs away until a man she understood to be an off-duty police officer arrived.
He "made himself big and yelled at the dogs," which succeeded in driving them away from Beaumont.
Beaumont's father, Chris Beaumont, said the dogs opened his son's head up. He applauded the actions of his "extremely brave" neighbour.
Chris Beaumont said he had seen too many dog attacks, and urged the Government to act to prevent similar attacks by dangerous dogs.
- Additional reporting Otago Daily Times
