Matt Kraemer, of Dunedin, said last Friday he was protecting his panicked wife, Jo, when he had poked the sea lion with a speargun spear.
He had also maintained his right to defend himself against a "berserk" animal.
Former trust chairman Steve Broni yesterday said he would like to discuss the situation with Mr Kraemer, mainly to learn more about what had happened.
Mr Kraemer said last night that he had acted solely in defence of himself and his wife, had only caused a small wound in the sea lion, and denied he had poked at the endangered mammal several times.
He was willing to talk to Mr Broni about the situation.
"I’m very interested in talking to these people," he said.
In a post on his own Facebook page last Friday, Mr Kraemer, a former candidate for the Otago Regional Council, said that a "particularly aggressive" sea lion had just "harassed me with lion-sized jaws" during a 30-minute swim back to the beach.
"It actually climbed out of the water and threatened to attack on the beach. I had to stab it with a spear to defend my terrified dive buddy!" he posted.
Mr Kraemer said his social media posts had sparked what he termed "hundreds" of replies, mainly taking issue with his actions.
He and his wife had had a "very scary" experience.
Mr Broni said that in the water, sea lions were curious about humans and could often be playful in their interactions, swimming close by but were not trying to attack humans, and humans were not a prey species.
On the beach, sea lions could also stage "bluff charges" to protect the space around them.
None of these actions were signs of a "berserk" creature seeking to attack, but were normal behaviours by sea lions, he said.
The answer was to move briskly away until the sea lion had moved off, he said.
Doc coastal Otago acting operations manager Mike Hopkins said sea lions were protected under the Marine Mammals Act.
If someone believed they had injured a sea lion they should report it as soon as possible to the conservation hotline 0800 DOC HOT (0800 362-468) or the Ministry for Primary Industries (0800 008333).
Doc biodiversity ranger Jim Fyfe said sea lions needed space and sometimes made "bluff charges" if people came too close.
Between humans, dogs and sea lions there was a big potential for cross-species misunderstandings, humans sometimes thinking they were under attack when they were not, Mr Fyfe said.
