Bus fares in Canterbury could be set to increase from an average of $2 a journey, to $8, to meet new revenue targets set by Waka Kotahi New Zealand Transport Agency.
Letters were sent to local councils and transport authorities late last month, asking them to increase their private share - that is, the proportion of the total cost of providing public transport that comes from things other than rates or government funding.
Currently, people can travel on any Metro bus across Christchurch, Selwyn and Waimakariri for $2 or less with a Metrocard.
The regional council, Environment Canterbury, has worked out a four-fold increase in fares would be needed to meet the new targets, which needed to be finalised by 19 December.
It said concessions would be available for under 25 years olds, community service card holders, tertiary students and total mobility card holders.
Public transport leaders across the country have requested an urgent meeting with the transport minister, in a strongly worded letter from Greater Wellington chair Daran Ponter, in which he called the target deadline unreasonable and unachievable for many.
Environment Canterbury councillor Deon Swiggs told Midday Report the council would do everything it could to bring that cost down through other income sources or cutting costs.
But as it stood, fares would increase four-fold.
"We could be potentially facing a full fare - that's before the concessions that people have such as gold cards or student fares or people under the age of 25, children, all of those concessions - of approximately about $8," Swiggs said.
Transport Minister Simeon Brown said last week an increase in fares was necessary to tackle the rising cost of public transport, without putting more burden on ratepayers and taxpayers.
"In 2017, public transport users contributed 40 percent of the operating costs, but by 2023 this had dropped to just 10 percent," he said in a statement.
He expected councils to keep those costs under control by using a "wide range of tools available to address rising costs, such as expanding advertising opportunities, partnering with businesses to fund targeted concessions, maximising retail spaces at transport hubs, and introducing commercial charging facilities".
His expectation was that NZTA would work with councils to set appropriate targets, and set the councils up for success to meet them.
NZTA acting group general manager for transport services Vanessa Browne said an increase was needed to support the record level of public transport expenditure already being invested (by central government) in the ever-growing costs of public transport.
She said increasing revenue could be done by other methods, not just raising fares - advertising, sponsorship, rental income and corporate schemes or commercial opportunities.
"By optimising services, reducing costs and raising revenue, [public transport providers] can create a more efficient and financially sustainable public transport system which delivers value-for-money for all of our communities," she said.