New Zealand head coach Gary Stead says it is time for the Black Caps to have separate coaches guiding the test and white ball teams to help ease the demands on staff.

Stead has held both roles since succeeding Mike Hesson in 2018, guiding New Zealand to the final of the 50-over 2019 World Cup and the inaugural World Test Championship (WTC) title in 2021.

He hopes to continue coaching New Zealand when his contract expires after this year's World Cup in India.

"I think it's time that we do need to split off and look at it," the 51-year-old told reporters in Wellington on Tuesday.

"I think the modern game is becoming very, very tough for players and coaches to try and sustain everything across that whole period of time and New Zealand Cricket and I are definitely talking about that as an option."

New Zealand capped the home test summer on Monday with an innings and 58-run win over Sri Lanka to sweep the series 2-0.

New Zealand's WTC title defence is already over but they won their last three tests of the cycle and can look forward to the next championship with optimism.

Stead will now turn his attention to coaching the Black Caps in three ODIs and three T20Is against Sri Lanka starting at Eden Park on Saturday, with a slew of regulars such as Kane Williamson absent to play in the Indian Premier League. Read full story

Stead suggested his preference was to continue coaching the test team if still in charge when the squad assembles for a tour of Bangladesh after the World Cup in October-November.

However, he said he would not rule himself out of the job if New Zealand Cricket wanted him to continue overseeing the white ball teams as well.

Despite the comprehensive series win over Sri Lanka, New Zealand's bowling depth remains a concern following Trent Boult and all-rounder Colin de Grandhomme's decisions to opt out of their national contracts.

Kyle Jamieson is recovering from back surgery while 37-year-old fellow paceman Neil Wagner is sidelined with a serious hamstring strain and carried a back problem through the home summer.

None of New Zealand's fast bowling reinforcements offered a compelling case for their retention, though Blair Tickner battled hard against the Wellington wind to take 3-84 in Sri Lanka's second innings on Monday.

Selectors opted against calling up Boult for the home test series against England and Sri Lanka, and Stead said it was still too early to confirm the former pace spearhead would join New Zealand's bid for a first 50-over World Cup title in India.

"Trent and I will be talking in the near future before he goes to the IPL and just trying to, I guess, work out where we both lie with expectations as well," he said.