New Zealand Cricket said that "after injuring his knee playing in the IPL in March, Williamson has made sufficient progress in his recovery to allow him to be included in the squad for the tournament starting in October."

Whether Williamson will play, however, is not yet certain. "Through this entire process I have tried to keep an open mind on when I might be able to return to cricket and not get too focused on one date or match," Williamson said. "Being selected doesn't change that and I know there's still work to do and day by day goals to tick off to get back on the field with the team."

The rest of New Zealand's 15-man squad will be named in Auckland on September 11.

Stead was cautious about Williamson being available for selection for their World Cup opener against England on October 5 in Ahmedabad.

"Kane has applied phenomenal dedication to his rehabilitation and has been supported by a strong group of experts around him," Stead said. "He's left no stone unturned in trying to get back playing cricket at the highest level. We are delighted to be in a place to select him.

"At the same time, he's also kept perspective about his recovery and hasn't wanted to rush or force his way back too early. As we've previously said, it's great he wants to play cricket for New Zealand in the long term.

"As we've said throughout this process we want to give Kane every bit of available time to aid his recovery. The World Cup is not a short tournament and we will continue to monitor his progress over the next month ahead of the first tournament match."

Williamson injured his knee on March 31, when he was fielding for Gujarat Titans in he opening game of the IPL season against Chennai Super Kings. He jumped up on the boundary to try and catch a ball that was going for six, landed awkwardly on his right leg, and went down immediately clutching his knee. He subsequently returned to New Zealand and underwent surgery in June.