Conway, 28, was cleared by the ICC to represent New Zealand in March and will be eligible for selection from August onwards. He was born and raised in South Africa, but decided to start afresh in August 2017 and moved to New Zealand, where he has starred for Wellington in domestic cricket.
Colin Munro and Jeet Raval have not received offers to renew their contracts for 2020-21, after underwhelming performances in the 2019 World Cup and home Test summer respectively. Todd Astle, the legspinner, has also been dropped from the contract list after retiring from red-ball cricket in January.
Jamieson, 25, made his international debut during the home series against India in February. He took nine wickets in the two-Tests series at 16.33 apiece, and was the most economical bowler in the ODI series that followed. Patel, 31, has played eight Tests and two T20Is, and has primarily been used as a second spinner in overseas conditions.
"It's really exciting to offer contracts to Kyle, Ajaz and Devon who have all impressed over the past 12 months," said Gavin Larsen, New Zealand's selection manager.
"Kyle's performances against the might of India were nothing short of outstanding and at 25 years of age he's certainly got a big future. We see Ajaz as the incumbent Test spinner at present and he'll be looking to stamp his mark on that spot after some superb efforts with the ball in the sub-continent.
"Devon's form with the bat across all three formats these past two seasons made him impossible to ignore and he's going to be a great option to add to the batting mix."
Under the terms of NZC's agreement with the NZCPA (the players' union), the 20 men offered deals have until May 22 to accept or decline the contracts, which officially begin on August 1. "The NZC contract review group… considered a range of factors including past performances, playing history, the playing schedule for the next 12 months and likelihood of players being involved during that period," a press release stated.
Women's contracts have also been discussed, with a list of offers set to be released next week.
New Zealand contract list, 2020-21: Tom Blundell, Trent Boult, Devon Conway, Colin de Grandhomme, Lockie Ferguson, Martin Guptill, Matt Henry, Kyle Jamieson, Tom Latham, Henry Nicholls, James Neesham, Ajaz Patel, Mitchell Santner, Ish Sodhi, Tim Southee, Ross Taylor, Neil Wagner, BJ Watling, Kane Williamson, Will Young.