But, the director of three-time Oscar winner Pan's Labyrinth, Hellboy and the new horror film Crimson Peak, knew he was carrying a trump card on that 2009 scouting trip to get the hotel to open its doors.
New Zealand's favourite son, Peter Jackson, was co-executive producer and co-writer of The Hobbit.
"Peter and The Hobbit are national treasures in New Zealand," he said.
Most people when they check into a hotel ask for a room with a view or a balcony, but what del Toro does is ask for haunted rooms.
The Waitomo stay was particularly scary because just his scouting crew was staying there.
"The hotel was empty, like in a horror movie," del Toro said.
Del Toro, 50, who eventually dropped out of directing The Hobbit films, with Jackson taking over, has only encountered two ghosts in his life.
One came during the night he stayed in Waitomo.
"I heard a horrible murder being committed in the room," del Toro said.
"I was actually terrified. I didn't sleep at all that night. What was strange was the next morning I was not tired, but I was wired and scared. I never imagined having those fears. It was absolutely terrifying."
That ghost experience, including the blood-chilling screams, are replicated in Crimson Peak, a film he says is a modern update on the classic romantic gothic movies that were a staple 30 or 40 years ago.
"There is the moment where you hear a murder in the bathtub," del Toro said.
"It comes directly from that moment in New Zealand."
The film is set in the late 19th century, with Australian actress Mia Wasikowska playing Edith, the daughter of a wealthy American businessman swept off her feet by the charming Englishman Sir Thomas Sharpe (Tom Hiddleston).
She agrees to move to his crumbling, haunted mansion in north-west England and, as well as dealing with the creepy Pan's Labyrinth-style ghosts, finds a foe in Sir Thomas' sister, Lady Lucille (Jessica Chastain).
"The gothic romance at one point in Hollywood was a very classic genre and I thought I wanted to make the genre in a more modern way, with a strong, modern central female character, different approach to sexual politics, violence and a little more sex," the director said.
Del Toro wrote the Crimson Peak script in 2006 just after Pan's Labyrinth, but Hollywood studios didn't want to touch his R-rated film, despite its relatively cheap US$50 million budget.
They wanted him to make something more teen-friendly.
After teaming up with Legendary Pictures on 2013's action-sci-fi Pacific Rim, del Toro and the production company headed by Thomas Tull agreed to make Crimson Peak the way he envisioned it.
There's another ghost experience in Crimson Peak based on a real experience, but it comes from a story del Toro's mother told.
In one of the first scenes of the movie a disturbing ghost visits a young Edith in bed.
"My mother had that experience when she was a child," del Toro said.
"She heard the ghost of her grandmother walk into her room.
"She felt the silk on her dress, smelled her perfume and felt the springs in the mattress give way to the weight of the grandmother and then felt her on her back, embracing her."
Lowdown
Who: Guillermo del Toro
What: Crimson Peak, his latest gothic horror
When: Opens Thursday
- AAP
