Players included in last year's list who are not contracted for 2014-15 include Doug Bracewell, Dean Brownlie, Grant Elliott, Peter Fulton, Bruce Martin and Hamish Rutherford.
A set criteria is used to rank players across all three forms of the game with test cricket receiving twice the weighting of One Day Internationals and Twenty20 Internationals.
The players with the 20 highest aggregate scores are then offered NZC contracts.
NZC General Manager National Selection Bruce Edgar said there were so many up-and-coming players pushing for selection after a promising year for the Black Caps which featured three back-to-back test series victories.
"We've had a very strong summer followed by the test series victory in the West Indies where a number of younger players put their hands up for consideration.
"Two of those integral to the series win in the West Indies were spinners Ish Sodhi and Mark Craig. While we accept that Mark and Ish are by no means the finished product, they are promising bowlers that we want to invest time in."
Edgar says that with a full tour against Pakistan in the United Arab Emirates coming up it was critical to select two test spinners. The year ahead also features a tour to England, a full tour by Sri Lanka, and short visits by South Africa and Pakistan in preparation for the major prize - the ICC Cricket World Cup co-hosted by New Zealand and Australia.
Also new to the contracted group are pacemen Milne and Henry who performed well when given the opportunity in limited overs matches last summer.
"Adam and Matt are two exciting young bowlers that if we manage well have got a big future in all forms of the game."
The addition of Neesham and Ronchi rewards their contributions over the past year, says Edgar.
"Jimmy and Luke are both consistent members of our shorter form teams and they've recently been selected in our Test squad as well.
Edgar says there was not enough certainty to offer Black Caps contracts to two opening test batsmen - instead just Tom Latham was confirmed in the 20.
"There'll be plenty of opportunities for the openers and others with domestic contracts to put their hand up on both the New Zealand A tour to England later this month and throughout the season in the domestic competitions."
The first round of Major Association contracts will be announced on 25 July.
The 20 players offered Black Caps contracts for the year 1 August 2014 to 31 July 2015 are:
Corey Anderson - Northern Knights, Trent Boult - Northern Knights, Mark Craig - Otago Volts, Martin Guptill - Auckland Aces, Matt Henry - Canterbury, Tom Latham - Canterbury, Mitchell McClenaghan - Auckland Aces, Brendon McCullum - Otago Volts, Nathan McCullum - Otago Volts,
Kyle Mills - Auckland Aces, Adam Milne - Central Stags, Colin Munro - Auckland Aces, Jimmy Neesham - Otago Volts, Luke Ronchi - Wellington Firebirds, Ish Sodhi - Northern Knights, Tim Southee - Northern Knights, Ross Taylor - Central Stags, Neil Wagner - Otago Volts, BJ Watling - Northern Knights, Kane Williamson - Northern Knights.
