A council press release in April heralded the coming electric buses as "state of the art" and the start of a transition to a low emission fleet.
On Friday Councillor Lyall Thurston told the Bay of Plenty Times the missed deadline in December was due to "a tight timeframe between awarding the contract to NZ Bus and the network roll-out".
Asked if he was satisfied by that reason for the delay, he said he was just "bitterly disappointed" the electric buses had not been part of the December rollout.
For the last three weeks, the council's staff have refused to give reasons for the buses' delayed arrival; first citing commercial sensitivity, then a wait for information from NZ Bus, then saying an update would be released "in the coming weeks".
It admitted last weekthe buses were not "shipped to the wrong country" as a council official reported to a February 8 meeting of the Public Transport Committee.
The day after the meeting, NZ Bus operations general manager Claire Neville told the Bay of Plenty Times that was "untrue".
After multiple rounds of questions, last week the council said the statement was based on "a verbal update from NZ Bus representatives in the Bay of Plenty", which was the only available information at the time and had since been corrected by the company's head office.
The general manager of NZ Bus' fleet, Ian Gordon, also would not specify the reasons for the delay this week.
"It is worth noting that EVs are bespoke, designed to meet a particular requirement and parts and manufacturing lead times can be very long."
Tauranga MP Simon Bridges said the lack of transparency from the regional council on the issue was "not good enough", while Bay of Plenty MP Todd Muller said if the buses were part of a commercial contract, there should be commercial consequences for late delivery.
NZ Bus is in the process of being sold by its owner, publicly listed infrastructure investor Infratil.
Infratil announced it was reviewing its ownership of NZ Bus last February, two months before the Bay of Plenty Regional Council's April announcement that it had awarded the contract for Tauranga's urban bus network to NZ Bus.
NZ Bus took over in Tauranga on December 10. On December 24 Infratil announced it had struck a conditional deal to sell NZ Bus to funds controlled by Next Capital for up to $240 million.
Subject to conditions, including Overseas Investment Office approval, the transaction was expected to be completed by around June 30.