A Mandurah war veteran who was mauled by a dog said he has been battling physical pain and mental trauma since the attack.

Great-grandfather Brian Dillon, 75, was standing at a Dawesville boat ramp last Wednesday evening when he was attacked by a Bullmastiff.

The dog latched on to his arm, making him fall off the side of the jetty.

The fall caused the Vietnam veteran to break a bone, leaving the pensioner —who has had four knee replacements — in agony.

"This would be the worst injury I’ve ever had in my life,” he told 7News.

Camera Icon The great-grandfather was mauled at a Dawesville boat ramp. Credit: 7News

Haunted by the viciousness of the attack, Mr Dillion said it had triggered nightmares where he has woken up screaming.

Mr Dillion said the dog's owner came over, but didn't give his details.

Despite the trauma he has experienced, Mr Dillion said he didn’t want the dog destroyed and admitted he was an animal lover.

His message for owners was simple — keep pets properly restrained.

The City of Mandurah has been plagued with dog attacks in recently.

Since July, there have been 143 dog attacks reported to its rangers, 23 more than for the same time period last year.

Camera Icon The great-grandfather was mauled at a Dawesville boat ramp. Credit: 7News Perth

A spokeswoman for the local government said it’s rangers were aware of the location of the dog but that they were still investigating.

Kalmpets Animal Behaviour Centre’s Dr Kate Lindsay said there was “no such thing as an aggressive dog”, just frightened ones.

“The dog is just as frightened as you,” she said. “If you are about to be attacked the advice is don’t turn your back,” she said.

“Keep them insight and move slowly backwards. Avoid shouting, hitting or kicking.”