The New Zealand cricket team has been dealt a major blow on the eve of their test series against world No. 1-ranked South Africa, with form bowler Tim Southee ruled out with a thumb injury.

The 24-year-old suffered extensive damage to his digit while diving in the field during the recent Plunket Shield match between Northern Knights and Wellington Firebirds.

Black Caps physiotherapist Paul Close said Southee landed heavily on his thumb, with scans indicating the ligament had fully ruptured and retracted.

"After consultation with New Zealand Cricket medical staff and a hand specialist it was decided the best course of action is for him to have surgery," said Close.

"He will commence rehabilitation immediately following the procedure, with a view to him returning to cricket during the home summer."

The operation is likely to keep Southee out for six to eight weeks.

His absence is a signficant blow to a side already missing the unavailable Ross Taylor and Jesse Ryder and the injured Daniel Vettori.

Despite appearing in only 21 tests, and out-of-favour veteran Chris Martin aside, Southee is the most experienced of New Zealand's pace attack.

New skipper Brendon McCullum has talked of him as vice-captain, saying he's "coming into his own".

Perhaps more importantly Southee is taking wickets, with 12 in last month's drawn series in Sri Lanka, including eight in New Zealand's dominant victory in the second test.

That haul leaves him with 65 wickets at a shade over 35 and a strike rate of 62.4.

Southee had been excused from the three-match Twenty20 series starting tomorrow morning in Durban due to the imminent arrival of his first child. He was due to join the test squad in time for the two-test series starting on January 2.

His role as a beligerent tail-ender will also be missed. He smashed 156 from No. 8 for Northern Districts, his maiden first-class century, in their Plunket Shield victory over Wellington this week, before going on to take seven wickets for the match.

Southee's absence is likely to mean Trent Boult leads the line, with more expected of Doug Bracewell, who has struggled to replicate his match-winning performance in the second test against Australia in Hobart last year.

A replacement has yet to be announced. Coach Mike Hesson may opt for the experience of Martin in the starting line up and bring Auckland paceman Mitchell McClenaghan into the squad. McClenaghan had been due to leave after the T20 series.

There may also be an opportunity for Otago's Neil Wagner to face his country of birth.