However, what emerged when the line was reeled in was an iPhone 5s with a name on the back of it.
"My friend said 'Do you know a Graeme Mansfield?'and I said I do!," Newton said.
Mansfield said he was in awe at the chances of not only the phone being hooked by a fishing line, but being hooked by someone who knew him.
"The chances of that happening would be a billion to one in a place like Taupo with that amount of water," Mansfield said.
Newton said he called Mansfield's office and got his cellphone number before calling him to tell him the good, and bizarre, news.
"He just about fell over when I told him," Newton chuckled.
Reunited with his phone Mansfield says he knows it sounds like a fishy tale and has a hard time convincing people the story is true.
"People you tell just don't believe it," he said.
Massey University distinguished professor Gaven Martin, whose expertise is statistics and mathematics, said the chances of this happening are "very slim".
"It's possible but it's incredibly unlikely," he said.
Either way Mansfield has said he's happy his phone has returned to him.
"It is a happy ending because I've got my own phone back, my trusty old phone. I'm not going to put it in a glass case or anything but I'm certainly not going throw it away."