Howarth, the former Surrey batsman who was New Zealand's most successful Test captain, announced his decision following speculation that he was to be sacked. He was half-way through a three-year contract.
His position had become untenable following series defeats against Australia, England and South Africa. On the recent South African tour, the Kiwis lost all their one-day matches and the Test series 2-1.
New Zealand Cricket, the national body, said it had accepted his resignation, but made no announcement on a successor. Speculation has focused on the former opening batsman, Glenn Turner.
New Zealand are due to face the West Indies in Auckland on Sunday in the first of three one-day internationals, to be followed by two Tests.
n Winston Benjamin saved the West Indies from disaster as he hit 74 runs and took four wickets as Auckland were trounced by 105 runs at Eden Park yesterday.
TOUR MATCH (Auckland, NZ): West Indies 206 for 9 (W Benjamin 74); Auckland 101 (W Benjamin 4 for 10, K Arthurton 4 for 26). West Indies won by 105 runs.Reuse content