Sawyer was appointed in June 2022 and after leading the side to a bronze medal at the Commonwealth Games that same year he guided New Zealand to their first Women's T20 World Cup title in 2024.
However, New Zealand were eliminated from the group stage of the 50-over World Cup last year and suffered another early exit in their T20 world title defence in June.
"Sawyer’s contract, which was set to conclude in December 2026, has not been renewed following a comprehensive review process," NZC said in a statement.
Sawyer was disappointed to be leaving but said it had been an honour to coach the team.
"This team means a lot to me and I’m really proud of what we have been able to achieve in the past four years," he added.