Fleming, 33, will set a new world record of captaining his 194th one-dayer, surpassing Sri Lankan Arjuna Ranatunga's mark, as both teams seek a win to nudge ahead in the wide open semi-final race from Group 'B'.
All four teams in the group - Sri Lanka, New Zealand, Pakistan and South Africa - are in contention for the two semi-final spots with three key games still to be played.
Sri Lanka and New Zealand have a 1-1 record from two matches, while Pakistan won the only match it has played so far. South Africa's lone game ended in a defeat.
New Zealand must beat Pakistan on Wednesday to stay in the hunt, irrespective of the result of Tuesday's match between Sri Lanka and South Africa in Ahmedabad.
The Black Caps upset world number two South Africa in their first match at the Brabourne stadium in Mumbai before losing to Sri Lanka by seven wickets at the same venue on Friday.
Pakistan overcame the absence of banned skipper Inzamam-ul-Haq and the drug-tainted pace duo of Shoaib Akhtar and Mohammad Asif to stun Sri Lanka by four wickets in Jaipur last Tuesday.
Stand-in captain Younis Khan said Pakistan was motivated to go the distance in the biennial tournament, regarded by the International Cricket Council as the second most important after the four-yearly World Cup.
"We can't wait to get on to the field, it's been a long time sitting out," said Younis after his team visited a local mosque under tight security on Tuesday to offer Eid-ul-Fitr prayers.
"A win over New Zealand will take us into the semi-finals, we can't afford to lose this one."
New Zealand, who finally have 14 fit players for the match, are banking on the cooler climate of northern Mohali and a wicket with more bounce than the one at the Brabourne stadium to secure victory.
Pace spearhead Shane Bond has recovered fully from the stiff back which kept him out of the first match. He returned tentatively for the second game and was thrashed for 47 runs in seven overs by the Sri Lankans.
All-rounder Scott Styris is also back to full fitness and will bowl on Wednesday after being kept out of the attack against Sri Lanka as a precautionary measure.
"All the 14 are available for us which is a good sign," said Fleming, a veteran of 255 one-dayers.
"The biggest worry for us is that we have been inconsistent in big tournaments. I think we are a side that gets a bit comfortable once it has won a game."
Fleming is confident the batting will click on what he considers to be a "very good wicket."
Totals of 195 against South Africa and 165 against the Sri Lankans meant the Black Caps fell for sub-200 scores batting first for the first time since May, 2003.
The likelihood of dew on the ground in the evening session of the day-night match means the toss may prove crucial because teams will want to bat second to take advantage of the wet ball that could hamper bowling.
Pakistan: Younis Khan (capt), Imran Farhat, Muhammad Hafeez, Mohammed Yusuf, Abdul Razzaq, Shahid Afridi, Kamran Akmal (wk), Shoiab Malik, Rao Iftikhar, Umar Gul, Naved-Ul-Hassan, Faisal Iqbal, Yasser Arafat and Abdul Rehman.
New Zealand: Stephen Fleming (capt), Nathan Astle, Shane Bond, James Franklin, Peter Fulton, Mark Gillespie, Hamish Marshall, Brendon McCullum (wk), Kyle Mills, Jacob Oram, Jeetan Patel, Scott Styris, Daniel Vettori, Lou Vincent
Umpires: Mark Benson (Eng) Rudi Koertzen(RSA). 3rd Umpire:Billy Bowden (NZ) and 4th umpire: Steve Bucknor(WI).
Match Referee: Ranjan Mudugalle(SL)