Larsen reiterated the bitter disappointment at the way New Zealand folded on the final day at the Basin Reserve last Saturday.
"There's a lot of work that has to take place between now and the first ball.
"We need more runs and the bowling needs to be tidied up in a general sense.
"We want to see greater fight, which is a hallmark of the good Black Caps teams and we've seen a lot of that in the last two or three years.
"We fought really hard for a day and a half at the Basin, but then dropped our guard."
Perhaps as a pointer to Larsen's remark that the work starts today, opener Tom Latham was down at the nets with batting coach Craig McMillan this morning. Most of the test players had headed home for a day off before reassembling in Hamilton.
Larsen said a raft of players had been considered by himself and fellow selector Mike Hesson. But the faith remains intact that no one could come in and improve the group which lost by eight wickets in Wellington, after drawing the first test in Dunedin.
Neil Broom gets another chance in Taylor's absence - Larsen pointing out if Taylor had been fit he would have been straight back in - and the selector liked what he saw from the Otago veteran in Wellington.
He was dismissed by two fine balls for 0 and 20 but "we have plenty of faith that he'll do the job at No 4", Larsen added.
Similarly Latham received a ringing endorsement, despite being in a deep hole with his form at present.
"We have 100 per cent faith in Tom. We think he's a classy player. He's in a rut, no doubt about that but his numbers speak for themselves. He's working hard. Internally I'm sure he's feeling it, anyone would."
There's no place for legspinner Ish Sodhi, on his home ground, the selectors arguing that they already have the best spinners in the squad, with veteran offspinner Jeetan Patel and left armer Mitch Santner.
"We talk about all the options. Yes he was talked about alongside many other players but we believe we have the right spin combination."
Both Colin de Grandhomme and Jimmy Neesham hae survived despite poor batting displays. De Grandhomme's seam bowling was tidy but the pair were also there to provide batting depth, and simply didn't deliver.
Their second innings dismissals to left arm spinner Keshav Maharaj were extremely disappointing. They live to fight another day, or at least one of the will with two spinners almost certain to be used in Hamilton.
Boult, key to New Zealand's bowling attack, is a "day to day" proposition but there's optimism he should be fit for Saturday.
"We're confident we can get him on the park," Larsen said.
New Zealand: (from) Kane Williamson ©, Tom Latham, Jeet Raval, Neil Broom, Henry Nicholls, Jimmy Neesham, BJ Watling, Colin de Grandhomme, Mitch Santner, Jeetan Patel, Tim Southee, Neil Wagner, Matt Henry, Trent Boult.
