New Zealand pace spearhead Trent Boult is available and likely to be selected for this year's 50-overs World Cup in India despite declining the offer of a national contract, head coach Gary Stead said on Thursday.

Boult, who opted out of his contract last year, was not included in New Zealand's updated list of contracted players on Thursday but had instead signed a "casual playing agreement", New Zealand Cricket said.

"He has indicated he's available for the World Cup," Stead told reporters.

"He's one of the best ODI bowlers in the world so barring injury, I think it's highly likely he would be part of our squad."

Boult and Tim Southee formed one of the most feared strike partnerships in international cricket over the last decade, helping New Zealand to the inaugural World Test Championship in 2021 and the finals of the last two 50-overs World Cups.

However, Boult was released from his contract last August at his own request, saying he wanted to spend more time at home with family and less time travelling.

Although picked for an ODI series in Australia last year and the T20 World Cup that followed in the same country, Boult was snubbed by selectors through New Zealand's home summer, even when an injury crisis hit the squad's pace bowling stocks during the test series against England.

Stead said Boult's international availability outside the World Cup was still being discussed and was dependent to some extent on his T20 league commitments.

But the coach left the door open for a possible return to the test squad for the left-armer, who has taken 317 test wickets and more than 250 in limited overs internationals.

"We're just still working through that ... The conversations are positive, though," said Stead.

"It's just marrying up what works and what 'readiness' means from our perspective around test cricket, in particular."

While Boult remains firmly in New Zealand's plans, spinner Ajaz Patel was dropped from the Black Caps' list of 20 contracted players after featuring in two tests and no white ball internationals last season.

Adam Milne was awarded one for the first time in five years, though, after a productive international season boasting 24 wickets in 16 white ball matches.

Players offered New Zealand contracts for 2023-24:

Finn Allen, Tom Blundell, Michael Bracewell, Mark Chapman, Devon Conway, Lockie Ferguson, Matt Henry, Kyle Jamieson, Tom Latham, Adam Milne, Daryl Mitchell, Henry Nicholls, Glenn Phillips, Mitchell Santner, Ish Sodhi, Tim Southee, Blair Tickner, Neil Wagner, Kane Williamson, Will Young.