Although he lived in Hamilton at the time, the Canadian-born author told the Rotorua Daily Post he would spend a week a month living at Rydges Rotorua and going to visit the TABs he supervised in the wider Bay of Plenty.
"Rotorua for me was kind of neat and it was a bit like when I was a kid and I fell in love with the place."
He said TVNZ approached him a couple of years ago wanting to use the book as the base for the Vegas series.
"They have really got what I was doing with the book and I think they've done a really good job of capturing it. It's never easy with a lot of people involved in a big production but I've been on set and I've seen the screenplay and was there for the welcome and a day of filming, and I think they've done a great job.
"It will be really amazing to see it on screen. And I love that debate - which is better, the book or the television show - so that will be interesting too."
When asked if locals should be worried about Vegas or his book portraying Rotorua in a negative light, Berard said "not at all".
"It is a book about a slice of humanity caught after a very stressful event and it is a very human story and it has in it a redemption tale and a love story as part of that story.
"Many of the local women who I knew really well were also concerned and one of them I based a character on, who has brothers in the gangs, said to me 'if you make me look bad I'm going to get you killed' but she said 'oh you made me look like a star'. She loved it."
Berard said one of the reasons he wanted to go with TVNZ's series was because they were filming in Rotorua and he wanted the series to show off the area and employ locals.
"Bring those 20 apprentices on board, film Rotorua. Some of the scenes I have seen are amazing and that's testament to the beauty of the place."
Inside the Black Horse won the 2016 Ngaio Marsh Award for Best First Crime Novel and was longlisted for the 2017 International Dublin Literary Award.
Berard is currently working on his second novel, The Diary of a Dead Man, and is speaking at the Auckland Writers' Festival in May.
Vegas will screen on TV2 on Monday at 8.30pm. It was filmed entirely in Rotorua and was produced by Greenstone Television with 10,000 Company and the Steambox Film Collective, with the support of NZ On Air and Te Reo Tātaki.