An autistic man who suffered extensive injuries after being mauled by two rottweilers in Winton yesterday was rescued by a brave neighbour and an off-duty police officer.

But one of the dogs responsible for the vicious attack was still loose in the rural Southland town last night.

Oliver Beaumont was taking his regular walk near his family's home in Great North Rd.

As the 22-year-old strolled along a nearby gravel road about 1pm, he was set upon by two dogs, understood by police to be fully grown rottweilers, one male and one female.

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.

Oliver Beaumont was attacked by Rottweilers in Winton yesterday. Photo / Supplied

The victim's father, Chris Beaumont, later said the dogs "opened his head up".

Burazor, who works with special needs students at Ruru Specialist School in Invercargill, said the young man was "completely covered in blood".

But Oliver Beaumont, who has autism, was not screaming.

"He doesn't react the same as other people would. There was no loud screaming."

For a minute that "felt like forever", Burazor tried to distract the two dogs from their attack.

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.

When he got out of his car, she handed him the steel. But he was unimpressed with her choice of weapon, replying "what the f*** am I supposed to do with this?" Instead, he "made himself big and yelled at the dogs," which succeeded in driving them away from Beaumont.

"He was so brave," Burazor said.

She assisted the injured and bleeding victim to her home, where she managed to staunch the bleeding from his head wound.

He suffered gashes on his face and puncture wounds on his arms, but thick jeans saved his legs from serious injury, she said.

Originally from Sweden, Burazor has lived in Winton for a only few months.

Ambulance officers arrived shortly afterwards to take Beaumont to Southland Hospital.

Police thanked the pair who went to his aid.

While the male rottweiler was in custody last night, a police spokesman said the female dog was still on the loose. They urged anyone who saw a female rottweiler at large in Winton to call 111.

A police spokesman said they were speaking last night to the owners of the dogs "who are upset by what has happened and are being helpful in assisting police and the council".

Beaumont's father applauded the actions of his "extremely brave" neighbour.

His son, who St John said had moderate injuries, had surgery last night.

Chris Beaumont said he had seen too many dog attacks, and urged the Government to act to prevent similar attacks by dangerous dogs.