Has Zac Franich already revealed The Bachelor's winner?

An expert in reading body language believes Zac Franich may have already revealed the winner of The Bachelor NZ.

Franich will chose in Sunday night's finale whether he will choose Lily or Viarni, the end of a process that saw him dating and eliminating 20 other girls on Three's romance reality show.

Zac Franich with Lily, one of The Bachelor finalists.

Speaking to Sarah, Sam and Toni on The Hits this morning, body language expert Suzanne Masefield watched footage of Franich discussing both Viarni and Lily.

She said Franich's words gave away clues about the winner when he spoke about them.

"He talked about Lily in the present tense ... then he started talking about Viarni in the past tense," Masefield said. "On a verbal point of view, that's a bit of a flag for me."

Things were different however, when it came to analysing his body language.

"He was looking up when he started talking about Lily, and away, which is almost like a distancing," she said.

"But when he was talking about Viarni, he was looking down ... his eyes sort of light up ... it can mean that he's trying to hide ... he doesn't want you to see what he's feeling."

Her ultimatum? "I would still go with Viarni."

Meanwhile, Franich has revealed he sought professional help after finishing filming the reality show.

He told Fairfax he didn't have time to deal with each break-up on the show.

"When Claudia went home, that was really hard. That was essentially a break up for me," he said about her elimination on Monday night.

"Once you finish a show you have to deal with all these unresolved feelings, and you've got to try and process that. That's been quite difficult for me."

Franich previously revealed he had suffered depression following a court case relating to his selection in the K2 1000 regatta in 2015.

"It was really not a good time," he revealed during an episode of The Bachelor.

"I was really lost, and just went lower and lower and found myself at the bottom of a really great big hole, and into a bit of depression."

* The Bachelor finale, 7pm, Sunday.