"When we thought about the value that Daryl brings to the team and the likely timeline as well, we're still hopeful he's right for the first game but probably more realistically the second game," Stead said.
Stead added that paceman Lockie Ferguson, who is missing the current series against Pakistan and Bangladesh, is also aiming for a return at the start of the World Cup campaign.
Fellow bowler Adam Milne left the field in the side's win over Bangladesh last night but Stead said that was just a precaution and he'll be fine to play in the series.
Mitchell was a standout while opening the batting during New Zealand's run to the final of last year's T20 World Cup, with their defeat by Australia coming after Devon Conway had suffered a broken hand in the semifinal win over England.
Conway has since assumed that opening role while Mitchell is now an integral part of the Black Caps' middle order, forming with Glenn Phillips and Jimmy Neesham a powerful closing trio.