Which of Arnel, Gillespie and Ellis will it be?

Twenty wickets. It does not even sound like that many, does it? Compared to the number a bowler can collect over a career, 20 wickets is nothing but for every Test match, it's all that matters. For New Zealand, finding the formula that will combine to cause 20 opposition wickets to fall is their biggest conundrum ahead of the second Test.

The first decisive step they took in that direction happened when they axed Tim Southee from the squad. That was the easy part. The swing bowler bled runs, had a few too many words to say about it and struggled with his action. The difficult part is deciding who will replace him, not because New Zealand are awash with options but because they have to find the exact fit, the person who will complete the puzzle perfectly, to enable them to take 20 wickets.

Brent Arnel appears the leading contender. Seddon Park is his home ground, he has been around the Test squad for a while and he tops the list of available bowlers from the Plunket Shield. Only Neil Wagner, who has yet to become eligible for the New Zealand team, has more wickets in the first-class competition. If the new selection policy is as scientific as Kim Littlejohn has made it out to be, Arnel would be the automatic pick.

"He [Arnel] knows this wicket pretty well," Ross Taylor, the New Zealand captain, said. "He's been a form bowler and [this is] probably is the best he's bowled for a few years. He bowls wicket to wicket and can hurry players up. He's little quicker than people think."

Another wicket-taker is Mark Gillespie. Despite a long absence from the New Zealand side, having last played a Test in 2008, Gillespie is seen as naturally attacking. His record against South Africa - a five-for in the only match he has played against them - can hardly come into contention, because of how long ago it was and how much both sides have changed since then.

"He is just a wicket-taker," Taylor said. "He's an aggressive bowler. He's probably not going to go for two or three runs an over but will pick up wickets. We need 20 wickets, so he'll be big part [of the plan] if he does play. He talks a big game and bowls pretty well in the nets. It has been a while [since he last played for New Zealand] and when he was in the side, at his peak, he was one of the best bowlers in the world and took a lot of wickets."

At the same time, Taylor hinted that Gillespie may fall victim to the wider plan despite his wicket-taking ability. "Twenty wickets is the key, but we've got to be consistent in our selections," he said. "I'm not saying he's an automatic selection, we will be talking about him."

The other candidate is Andrew Ellis, who has yet to play a Test for New Zealand. Although his scalps do not number anywhere near the other two (12 wickets in the Plunket Shield compared with 32 and 30), he brings in the important value addition of being able to bolster the batting line-up. "He'd come in and bat at eight. He's more a 'pick up a couple of wickets and block up an end' type of a bowler in the longer version," Taylor said. "That is a consideration and if he does come in, the balance of the side is pretty good."

With New Zealand only going in with five specialist batsmen, Taylor has appeared concerned about the lack of depth in the line-up. He emphasised that more responsibility has to be taken by the batsmen. "With batting, we've still got get out and bat four sessions," Taylor said. "We didn't do that in Dunedin.

"With ball, it will be little easier to swing it than in Dunedin with all the wind. With the amount of cricket that has been played here, the block [surface] is quite abrasive so reverse swing will come into it."

With some suggestions that the ball will seam more, others - like Taylor's - that it will swing, the only thing the Hamilton strip is not being predicted to do is offer turn. For that reason, Tarun Nethula will have to wait to make his Test debut. The legspinner seems consigned to the drinks cart with Rob Nicol being talked about as the possible second tweaker.

"With the cricket that's coming up [for New Zealand], Rob brings a spin element into it as well," Taylor said. "Two games in Caribbean, and India and Sri Lanka … [for a] second spinner, if don't decide to go with Nethula, Rob comes into it. He opens batting and [doubles up] as a second spinner. We have a lot of options."