New Zealand all-rounder Daryl Mitchell is a doubt for the Twenty20 World Cup in Australia starting this month after fracturing a finger in training on Friday.

Mitchell was ruled out of a tri-series also involving Pakistan and Bangladesh in New Zealand this week as a warm-up for the global tournament.

The 31-year-old suffered the injury while batting in the nets in Christchurch.

He will remain in a cast for at least two weeks, meaning it may not come off before the Black Caps' opening World T20 match against Australia on October 22.

Medical staff will monitor the progress of Mitchell, who has enjoyed a productive 18 months in all three international formats.

Coach Gary Stead said it would be a blow if their hard-hitting batsman and medium-paced bowler was ruled out of the tournament.

"Daryl's become a really important player to our T20 unit and we're certainly going to miss his all-round skills and versatility in the tri-series," Stead said.

"With our first game of the World Cup in just over two weeks we need to take some (time) to consider Daryl's recovery timeline and his potential involvement in the tournament."