Kane Williamson and Tim Southee were included Monday in an experienced New Zealand squad for next month's 50-overs World Cup in India.

Williamson will captain the Black Caps despite still working his way back to fitness after a serious knee injury last April.

The 33-year-old led New Zealand in their nail-biting defeat by England in the 2019 World Cup final and was named player of the tournament.

Williamson's return to the crease will boost the Black Caps as he has scored more than 6,500 runs in one-day international cricket.

New Zealand coach Gary Stead said it is unclear whether Williamson will be ready in time for their opening World Cup game against England on October 5 in Ahmedabad.

"We haven't put a date on whether he will be available for that first game or not," Stead told reporters on Monday.

"That's still three or four weeks away and time will tell a little bit closer, but he is doing everything in his powers to make that happen."

Southee, New Zealand's Test-match captain, leads a powerful bowling line-up alongside Trent Boult, one of the world's best ODI seamers.

Boult returned to the Black Caps by taking three wickets in Sunday's 79-run defeat to England when he knocked the top off the hosts' batting line-up on his 100th ODI appearance, his first for nearly a year.

"He's a real weapon for us with the new ball. It was very pleasing to see," Stead said of Boult's bowling performance to dismiss England's Jonny Bairstow, Joe Root and Ben Stokes.

All-rounder James Neesham, who came within a whisker of glory for New Zealand when the 2019 World Cup final was settled by a tense Super Over, also mades the 15-man side.

Only six of the squad will be playing at their first ODI World Cup, while this will be their fourth for both Southee and Williamson.

New Zealand squad:

Kane Williamson (capt), Trent Boult, Mark Chapman, Devon Conway, Lockie Ferguson, Matt Henry, Tom Latham, Daryl Mitchell, Jimmy Neesham, Glenn Phillips, Rachin Ravindra, Mitchell Santner, Ish Sodhi, Tim Southee, Will Young