Key Black Cap Daryl Mitchell will miss the second test against South Africa and the Twenty20 series against Australia because of an ongoing foot injury.

New Zealand management had hoped recent periods of rest - including sitting out the fifth T20 against Pakistan last month and the Super Smash finals - would allow the injury to heal.

However, 32-year-old Daryl was still experiencing discomfort during the 281-run first test win at Mount Maunganui, prompting medical staff to recommend a focused period of rehabilitation.

Black Caps coach Gary Stead says the decision was based on a long-term view to ensure Mitchell - ranked fourth in the ICC's test batting rankings - is fully fit for the two-test series against Australia starting on February 29.

"Daryl is a hugely important member of the squad in all three formats and ensuring he is in the best shape is vital with the period of matches to come," says Gary.

"Based on the schedule ahead, we feel now is an appropriate time for Daryl to complete a period of rehabilitation."

Daryl's place in the squad for next week's second test against the Proteas in Hamilton will be taken by Canterbury pace bowler Will O'Rourke, whose international debut came in the ODI home series against Bangladesh in December.

Under Black Caps planning, Will was to join the squad for the Seddon Park test anyway, but to replace another seamer.

The entire bowling attack will now travel to Hamilton, leaving Gary with some challenging selection decisions ahead of day one on Tuesday.

That includes his batting lineup, where Will Young is the only contender to replace Mitchell, who batted at number five at Bay Oval.

Will, a specialist opener, could bat down the order or push one of the first-test openers - Devon Conway or Tom Latham - further down.

RNZ