One of the lawyers who represented Teina Pora, wrongly convicted for murder, is taking on Scott Watson's application for mercy.

Jonathan Krebs says he became interested in Watson's case after reading his application for a Royal Prerogative of Mercy.

Watson is in prison for the murders of Olivia Hope and Ben Smart, who disappeared on New Year's Day, 1998.

The application, to Governor-General Dame Patsy Reddy, challenges whether two blonde hairs found on Watson's boat were Hope's.

"Having read that and other material others have prepared I believe it's certainly something that's worth taking forward," Krebs said.

Krebs said the near 20-year-old old case means a lot of work behind the scenes before advancing the application early next year.

Private investigator Tim McKinnell will also provide a "fresh look" at the case. McKinnell's investigative work also played a part in clearing Pora's name after his conviction for the murder of Susan Burdett.