Africa (for the World Cup) in a confident mood," Ganguly said ahead of Wednesday's day-night game at the Westpac Stadium.
India are still searching for their first win of the tour, having lost the two-Test series 2-0 before trailing 4-0 in the ongoing seven-match series.
"Obviously, we are keen on returning to the winning ways before we go to South Africa," said Ganguly.
"We haven't had a series in the last year in which we haven't won a match. There's motivation to do well in the next three games and the World Cup."
Indian batting star Sachin Tendulkar is likely to return after missing the first four one-dayers due to an ankle injury.
"His presence will definitely strengthen the side. He is a great player and an important member of the team," said Ganguly, who seemed more worried about his side's batting than bowling.
"We have to make sure we bat the full quota of 50 overs which we have not done in the previous matches," said Ganguly.
"Our approach should be not to lose early wickets. An important thing on these pitches is we should get a total of 180-200 considering that the New Zealand batsmen also have not had much runs under their belt."
New Zealand captain Stephen Fleming said he expected an improved batting performance from India despite having steamrollered them in the previous matches.
The hosts won both Tests inside three days and outplayed the tourists in the first four one-dayers.
"I would have liked India to fire, but that was missing because of the wickets and the way they had played," said Fleming.
"We also played on the same pitches and did better. We have created areas where they have lost confidence, especially their batting unit. I think it was a great effort by our bowling unit and our planning to expose those areas."
Fleming said India were capable of providing a stiff competition and putting his team under pressure in the remaining games.
"The opposition has been written off, but I still think they are capable of providing a good competition. Our job is to keep playing well and try to achieve a few more things."
New Zealand made one change from the team that won the fourth game by seven wickets at Queenstown on Saturday, including fast bowler Shane Bond in place of out-of-form Craig McMillan who scored just 31 in four one-dayers.
Bond returned to the squad after missing the last two matches due to a side strain.
"We have to look at the way we use players in the next three games," said Fleming.
"Hopefully, we can polish certain areas in these matches. We can get a realistic view of where our batting, bowling and fielding stand before the World Cup."
New Zealand (from): Stephen Fleming (capt), Nathan Astle, Mathew Sinclair, Scott Styris, Chris Harris, Brendon McCullum, Jacob Oram, Andre Adams, Kyle Mills, Daniel Vettori, Shane Bond, Daryl Tuffey.
India (from): Sourav Ganguly (capt), Virender Sehwag, Dinesh Mongia, Sachin Tendulkar, Rahul Dravid, Mohammad Kaif, Yuvraj Singh, Ajit Agarkar, Harbhajan Singh, Javagal Srinath, Zaheer Khan, Ashish Nehra, Anil Kumble, Venkatsai Laxman, Sanjay Bangar, Parthiv Patel, Rakesh Patel.