The guide dog received seven stitches to a leg. Photo: supplied

A legally blind woman says she was ''screaming'' for someone to help her and her guide dog after they were attacked by a crossbred dog on the loose.

The 42-year-old woman, who did not wish to identify herself or her dog, said even after two men came to her aid and forced the dog off, the crossbreed kept circling and wanted to continue the attack.

''I was swatting it away and screaming 'Help, help','' she said.

''It just kept coming in and coming in. It just wouldn't go away and it felt like forever before anyone came to help me. It was so scary.''

The woman and her 6-year-old female black Labrador were walking their usual route in South Dunedin on Wednesday and had stopped at the intersection of Bay View and Prince Albert Rds when the attack happened.

''I always know when there's [another] dog around. [My dog] gets excited and starts wagging her tail. I assumed it was with a person.''

The woman described the growling noise when the two dogs engaged as ''really scary''.

Her dog received seven stitches in its right front leg and the woman said it could have been worse had she not put her dog between her legs and keep its head facing the other dog.

The woman was not hurt. ''It was not interested in me at all.''

She believes the 20kg tan-coloured dog was not wearing a collar.

It was not the first time her ''placid'' dog had been attacked.

Last year, a ''big bullmastiff sort of thing'' attacked it on her property.

A previous guide dog she had about four years ago was also attacked.

Her present guide dog was ''so lovely. She loves children [and is] great with people.''

The woman did not blame the crossbred dog for the attack, but hoped when it was found the owners would keep it fenced in.

Since the attack, she had been given a couple of days' sick leave from her job as a support worker and her dog was on ''light duties''.

''We will be a bit wary. I have to just carry on,'' she said. ''It was a really scary situation. I wouldn't wish it on anyone.''

Blind Foundation national manager Paul Metcalf said attacks on guide dogs by other dogs could be damaging for their confidence.

''Quite often we get dogs running up and barking and being quite aggressive,'' Mr Metcalf said.

''[An] attack can have a significant impact on its confidence. It's almost setting itself up thinking 'oh great, is this dog coming to get me?'.''

Mr Metcalf said in some cases a dog's confidence was knocked so badly it had to be ''decommissioned''.

''It's really important that dog owners keep their dogs on a leash.''

Dunedin City Council senior animal services officer Peter Hanlin said once the dog and its owner were found, if it was registered he would be able to see if it was classified and if there were prior incidents. The owner could be prosecuted.

Mr Hanlin said it was not his decision to destroy a dog and, if need be, it would go through the courts.

The council was keen to hear from anyone with information about the offending dog and its whereabouts.

rhys.chamberlain@odt.co.nz