IMO if Pakistan can concentrate on playing cricket then they would deserve to be slight favorites.
Their squad is fairly settled & in form in both forms of the game, so I would say they are at full strength apart from Razzaq's illness. They have 2 genuine quicks in their opening bowling attack with decent back up, Kaneria is a class leggie, and their batting lineup is capable of scoring heavily with their new palyers in the top order performing well since their Home series v RSA.
NZ pitches are traditionally low & slow & don't offer as much pace & bounce for the seamers, nor do they support as much grip & turn for the spinners. However Pakistan have done well as their attacks have had enough class to get the best out of the pitches, and are a step above what the local batsmen face in domestic conditions.
This will be the first Away series for this squad and Pakistan are a bit like the French Rugby Union side - they do not travel well & can be hot & cold. It will be interesting to see how they deal with their internal politics following the resignation of the Chairman during the recent ODI series.
Last time out they dominated the opening exchanges until their internal politics disrupted the squad & performances. This lead to some 'curious' selections & laxidasical play in the last test in which they were soundly beaten.
It's also curious to note that NZ were below strength at that time with Sinclair in his 2nd series, and the bowling attack was still struggling to rebuild as it was the 2nd series after the RSA Tour. From memory I don't think Cairns, Vettori or O'Connor saw the series out following on from the Home series v WI.
This current NZ team will also be below full strength with the 'class' batsmen & Captain being unavailable (Fleming & Astle). Similarly NZ's 'class' seam bowler is out (Bond), and Cairns continues to struggle to find form with bat or ball. Furthermore NZ will have a new Coach for this series so this will be an unknown factor for the team.
While I'm confident the replacement players & Captain will step up to the mark, IMO the telling factor could be the loss of Fleming's leadership & influence as he provides that bit 'extra' that lifts the performance of this side.
When on their game Pakistan can beat any team, but they can become emotionally brittle when placed under consistant pressure. NZ have a good record of 'strangling' the opposition & it will be interesting to see if they have the firepower to be able to maintain this.
The Test series should be a good contest, but I'm not so sure about the ODI series, as I do not think NZ resolved any of their dilemas on the recent ODI series in Pakistan & are still looking for options & answers.