"It is one of the options open that we are currently actively considering," he said.
Mr Cook said Watson's other options were for a judicial review of the original prerogative and further appeal, but this was very difficult given he has exhausted avenues.
Watson's father said while he lacked confidence in the justice system, they "had" to have another go at the prerogative of mercy.
"With the publicity the article generates hopefully it will bring out of the woodwork more information,' he said.
"As far as the justice system is concerned I don't have a lot of faith, but we'll keep dripping on the rock. You get used to a kick in the guts."
North & South journalist Mike White told Radio New Zealand Watson was upset with the justice system.
"He feels very upset that he's still in jail despite so much evidence that was presented at trial [is] now being questioned and undermined, yet the authorities are incredibly reluctant to do anything," he said.
"He's hoping that by again bringing his case to public light, that perhaps there'll be some interest from someone who was involved in the case, who might be brave enough to come forward to say something."
When asked if he thought Watson was guilty of the crime, Mr White responded: "Look, I've never taken that step. I'm not God, I wasn't there, I don't know exactly what happened."
However, he said speaking to Watson had swayed his view that he was definitely guilty.
"All I can say is that I've gone on this long arch from being utterly convinced Scott Watson was guilty at the time through to now, doubting the evidence against him and being very unsettled about his conviction," Mr White said.
"The more I've learned about this case...you realise that there's precious little that actually still stacks up as evidence against him."
Smart and Hope vanished after boarding a yacht with a stranger in Marlborough Sounds, but Watson insisted it wasn't him.
Watson said in the interview that he believed he was picked by police because he was an easy target.
"I think it was because I had a criminal record," he told North & South.
"And I was (at Furneaux Lodge) alone and I left alone. I told them that. Basically I was an easy target for them, I was the easiest person that they could pick."