The government has slashed $47 million in funding that would have aimed to improve bus drivers' conditions over the next three years.
The previous Labour government had ring fenced $110m between 2022 and 2027 to improve pay and conditions for bus drivers.
The first tranche of money had gone to increasing base wages in city centres to $30 an hour and $28 dollars an hour in the regions.
The rest of the money was set to address problems with split shifts and payments for working extra hours.
In Budget 2024, the coalition government cut the funding back to $63m, committing to continuing to fund the base driver wage increases but not the other initiatives.
The Ministry of Transport told RNZ the government believed these forms of compensation were better addressed over time through contract negotiations.
Transport Minister Simeon Brown said $15m had also been allocated to retro-fit driver safety screens, install new or improved toilet facilities for drivers, and build or upgrade break and meal room areas.
Greater Wellington Regional Council chairperson Daran Ponter said it was looking for the government expenditure to deal with split shifts.
Ponter said if that money was no longer there it would make bus driving less attractive.
"[Potentially] result in us in a spiral once again where we are losing drivers and finding it difficult to attract drivers into the network."
During 2022 and 2023 Wellington bus services faced a major worker shortage where at its peak the network was short 130 drivers.
In late 2022, 181 services were also suspended to give passengers more certainty about their buses.
Ponter told RNZ this situation could return if worker conditions were not maintained.
"We have normalised the network over the last nine months, [but] we could fall back just as quickly because we have ended up being too mean with drivers."
Drivers could easily end up attracted to other workforces, including in Australia, he said.
Bus & Coach Association New Zealand chief executive Delaney Myers told RNZ it was looking forward to discussions around minimising split shifts.
"There was investment set aside specifically for that purpose, so we are disappointed to see that that's no longer on the work programme."
Myers said the number of bus drivers in New Zealand was currently OK, but the system was fragile.
"We do need to keep making improvements if we are going to continue to attract and retain drivers and one of those key things is minimising the need for drivers to work split shifts."
Green Party Transport spokesperson Julie Anne Genter told RNZ to have a well-functioning public transport system, bus driving needed to be attractive.
"Because of the split shifts and low rates of pay in the past we have had times when we have had huge numbers of bus cancellations because there were insufficient numbers of drivers."
Genter said the government had clearly allocated less money and resource to bus drivers' pay and conditions than the previous government.
Environment Canterbury said without further information from New Zealand Transport Agency Waka Kotahi it did not expect any impact on rates because of the change.
Auckland Transport said its understanding was that this did not impact "significant improvements" that it has made alongside government to improve bus driver wages over the last few years.
It said bus drivers played an essential role in keeping Auckland moving and that there have great improvements in the past year with bus passenger numbers at the highest point they have been since 2019.
"It is important that we continue working together as a sector to maintain our essential workforce."