It had invested in Air NZ's Starfish Programme that gave regular discounts on regional flights but it was dumped in September by the carrier and Trustpower's spend was beginning to exceed budget, he said.
"As a consequence, we are reviewing our travel arrangements, in terms of who we deal with, how we travel, and how we can curtail air travel ... Our discussions to date with Air NZ have been rigorous to say the least, and the energy we are putting into those discussions is elevating rapidly in line with our increasing costs."
Mr Crosby reckoned "there is room for movement downwards".
Tauranga Airport manager Ray Dumble said the cost of flights was a hot topic right through regional New Zealand and "is something the regional airports and the New Zealand Airports Association are continually lobbying Air NZ about".
Tauranga was primarily served by 50-seat Q300 aircraft with one 19-seat Beechcraft and one 68-seat ATR on an average weekday, he said. On an average weekday there were 13 arrivals and departures in total - six flights to Auckland, five to Wellington and two to Christchurch.
Air NZ spokeswoman Imogen Dennis said the airline would progressively replace the remaining Beechcraft aircraft operating between Tauranga and Auckland with 50-seat Q300 aircraft that would add an extra 532 seats per week.
Tauranga Chamber of Commerce chief executive Dave Burnett said Tauranga would gain from Air New Zealand's decision to cut flights in other parts of the Bay of Plenty.
Fare go
*Tauranga to Wellington: $194
*Auckland to Wellington: $129
*Tauranga to Christchurch: $249
*Auckland to Christchurch: $229
Cheapest one-way flights available for flights on November 24 as listed on www.airnewzealand.co.nz yesterday.
Air NZ
From February 1 you can fly to "really want to be there events" on a confirmed fare available 90 minutes before departure for $169 for a single one-way sector or $249 for two or more sectors.
- Source Air NZ