More than you'd think! Most of the novels are reprints of the source work with some images from the TV adaptation and a "As Seen on TV" banner, but amongst them are a few original "Based on the TV series" books. Thanks to Geoff for the suggestions so far, and if you know of any book that we are missing please add a comment!

Title
A Bit of a Dagg (1976-08-09)
A Taste of New Zealand (?)
African Journey (1990)
Alison Holst's Cooking Class (1988)
Annabel Langbein: The Free Range Cook (2014-2017)
Bad Seed, The (2019)
Bailey, Judy
Bear and Cindy and the Blackiwog (196?)
Beauty and the Beast (1976-1985)
Billy T James Show (1981-88)
Bon-Appetit (1976)
Bread and Roses (1993)
Bro'Town (2005-)
Bumble (?)
Captain's Log (2001-2)
Casketeers, the (2018)
Champion, the (1989)
Children of Fire Mountain (1979)
Children of the Dog Star (1984)
Cooper, Terence
Country Calendar (1966-Now)
Country Fare (1986)
Cowboy Bebop (2021)
Cryer, Max
D'Audney, Angela
Dawson, Charlotte
Deep Blue: A South Pacific Odyssey (1995)
Deepwater Black (1997)
Dig This (1975-1985)
Entertaining with Kerr (1959-68?)
Everson, Pat
Ewing, Barbara
Expressions of Sexuality (1985)
Fair Go (03-Apr-77-Continuing )
Fire-Raiser (1986)
Five O'clock with Jude Dobson (2000 - 2001)
Flight of the Albatross (1995)
Foodtruck, The (2011-12)
Foreign Correspondent (2004 - ?)
Fresh and Fancy Fare (1986)
Frontier of Dreams (2005)
Gardening (1968-74)
Get Fresh (2010)
Ghost Hunt (2005 – 2006)
Glide Time (1978), Gliding On (1981-84)
God Boy, the (1976)
Gone Fishin (1993 - Now)
Goodnight Kiwi (1976-94, 2007-)
Governor, the (1977)
Hairy Maclary (1996)
Hanlon (1985)
Happy Yoga (1978)
Haunting of Barney Palmer, The (1987)
Hawksby, John
Heartland (1992 - 96)
Here's How (1966-?)
Hudson and Halls (1976-86)
Hunger for the Wild (2006)
Hunter's Gold (1976)
Ice TV (1996 - 99)
Ihaka: Blunt Instrument (2000)
Islands of the Gulf (1965)
Jaquie Brown Diaries, The (2008-09)
Jesus: The Cold Case (2011)
Jo Seagar Cooks (2006)
Joe and Koro (1976-78)
Journeys in National Parks (1987)
Kaitangata Twitch (2010)
Keeping Up With the Kaimanawas (2015)
Kiwi Kitchen (2006)
Landmarks (1981)
Letter to Blanchy (1996)
Lifestyle
Living Earth, The (1992-94)
Looking at New Zealand (1967-)
Lost Children, the (2006)
Luminaries, The (2020)
MacKenzie Affair, the (1977)
Mad Dog Meets Rotten Fred and Ratsguts, The (1978)
Maddigan's Quest (2006)
Maggie's Garden Show (1992-2003)
Mainland Touch, The (1978-88)
McMillan, Bill
McPhail & Gadsby (1980-85,1998)
McPhail, David
Millennium Moments (2000)
Milly, Molly (2008-?)
Moa's Ark (1990)
Moon Jumper (1985 - 86)
Mucking In (2004-2009)
Mune, Ian
Musical Variety
New Zealand on a Plate (2010?)
New Zealand Wars, the (1999)
Nice One, Stu! (1973-77)
NZ Detectives (2010-11)
Off the Radar (2007)
On the Mat (3/7/1975-84)
One Man's View (1975)
Outdoors with Jeff (????)
Outrageous Fortune (2005-2010)
Pavlova Paradise Revisited (2002)
Play School (1975-1990)
Police Ten-7 (?)
Politically Incorrect Parenting Show, the (2011)
Public Eye, the
Real Food for Real People with Jo Seagar (1998-99)
Revolution (1996)
Rigold, Bunny
Schofield, Phillip
Shortland Street (1992-Now)
Sinclair, Graeme
Slipknot (1967)
Spies and Lies (2010)
Sports
Spot On (1973-1988)
Steel Riders (1987)
Studio One (196? to ?)
Summer Cooking (1990?)
Sweet Tooth (2021 - )
Taste New Zealand (1999-2003)
Telfer, Brendan
Terry Teo (1985-86)
Terry Teo (2016)
That's Country (1976 - 1983)
Thunderbirds are Go (2015-2020)
Thyme for Cookery (1971
Toogood, Selwyn
Topp Twins (1997)
Tribe, the (1999-?)
Uncharted With Sam Neill (2018)
Under the Mountain (1981)
Vaughan, Rod
Vegas (2021)
Weather Presenters?
What Now? (1982-Continuing )
Whitehouse, Davina
Wild South (1981-97)
Wild Track (1980 - 1991)
Winners and Losers (1976)
Wonderful World of Fred Dagg, the (1975/09/30 - ?)
Woolf, Ray
Worzel Gummidge Down Under (1986-87)
Young Hercules (1998-99)