Black Caps fast bowler Neil Wagner has been ruled out of the second test against Pakistan.

Wagner, bowling with two broken toes throughout, finished with figures of 4-105 from a combined 49 overs in the first test and required multiple rounds of pain-killing injections to keep him on the field.

However, his heroics will end there after the Black Caps announced a rest for their premier first-change bowler in the second test beginning January 3 in Christchurch. His injuries are expected to take up to six weeks to heal.

"I'm not sure there's too many individuals that could what he did in that test match," Black Caps coach Gary Stead told media on Thursday.

"I guess the pain, the injections he was getting were wearing off each time... and we can't have him going through that again for this test match.

"We want to be sensible about it. He probably needs five or six weeks of healing now to be right for the end of the season.

"He just showed how tough he really is and how valuable he's been to New Zealand for a long, long time. We'll miss him enormously."

Stead says Wagner's replacement will be named early on Friday and expects the side to maintain the existing balance within the squad.

"I think it's likely it will be a like-for-like replacement, so you imagine it is going to be a pace bowler."

Whoever that replacement is, they will have large boots to fill. Since the start of 2018 Wagner has taken 75 wickets at an average of 23.36, often in the role of workhorse with a used ball for the Black Caps.

The favourites to sub in to the squad appear to be Matt Henry, who is back from injury, Doug Bracewell, who hasn't played a test for more than four years, or Ed Nuttall, a like-for-like lively left-armer.

All three of those options have been in the wickets recently for New Zealand A.

Meanwhile Stead put to rest any concern over the health of all-rounder Mitchell Santner who was seen nursing sore fingers during the final of the Tauranga test.

"I think TV probably made a little bit more of that than what it was. He's a bit sore but it didn't affect him being able to bowl at all."

The Black Caps lead the series 1-0 and need a further victory at Hagley Oval to keep alive their hopes of appearing in the World Test Championship final at Lord's in June 2021.