By the time Liedenberg made her next call, the man was already injured.
Paramedics turned up soon after, followed by the police, she said, but DoC staff arrived only after the man was taken to hospital.
Ambulance spokeswoman Anita Halbert said the man, in his late 70s, suffered serious lower-leg injuries.
He was taken to Taranaki Base Hospital in a serious condition.
Police kept armed watch on the fur seal until ranger Gareth Hopkins took over.
DoC spokesman Darryn Ratana said efforts were made to encourage the fur seal back to the water.
"Our thoughts go to the gentleman who was attacked and to his family, hoping for a speedy recovery," Ratana said.
Fur seals had huge teeth and could have a very nasty bite, Ratana said. As well, sea mammals could carry diseases.
Usually they would attack only if provoked but, in this case, the victim was simply walking when the seal ambushed him, Ratana said.
Some locals had been asking for fencing but that was not needed, he said. "It is a lovely walkway and I think the people of New Plymouth want to keep it the way it is."
Ratana said he would discuss improved warning signs with the Taranaki District Council.
