Some bus fares are rising by 10 per cent despite diesel being at its cheapest since 2009.
Auckland Transport says the changes are to make fares fairer and are being made in preparation for the change to a simpler zone system.
At the end of the month, bus passengers travelling one to four stages and paying with a HOP card will notice a 10c increase. And people paying cash to travel three stages will be hit with a 50c price rise to $5.50.
Children's monthly train passes will also jump - an all-zone Hop pass goes from $110 to $130 when the changes are made on February 28.
Fares also rose in March last year, when Auckland Transport bumped up adult cash fares by 25 per cent on buses and train single-stage trips to encourage more passengers to use Hop cards, which offer a 20 per cent discount on the trip.
Councillor Chris Darby questioned the need for fare rises when bus and ferry operators' diesel costs have fallen 40 per cent since June 2014.
AA's February petrol-watch report says diesel is the cheapest it's been since 2009.
"In 2014 operators and Auckland Transport took great pains to explain the impact of sky-rocketing diesel prices on operational costs," Mr Darby said. "Auckland Transport's seemingly innocuous announcement of fare increases ... contains no logical explanation of why fares are being increased."
Auckland Transport spokesman Mark Hannan said the fare rise followed an annual review required by the Regional Public Transport Plan which takes into account operating costs, the cost of living and any infrastructure improvements.
"The review looks at all the costs of operating the public transport network, not just the price of fuel, with the largest single cost being labour.
"Auckland Transport purchases services from transport operators so as their costs increase, so too do ours."
Auckland Transport's Metro general manager, Mark Lambert, said this month that the price increase would "make it easier for passengers" when fares change from stages to zone-based later this year.
Mr Hannan said the new, cheaper contracts for the South Auckland bus network which were signed yesterday did not factor into the increase because the savings reduced the public subsidy.
He said the public subsidy for the South Auckland service was $20.3 million a year, but under the new contracts - which come into effect from October - the subsidy would fall to $17.2 million, which would reduce the overall cost of operating by more than $3 million.
• The inner-city and airport fare zones will be removed; a one-stage fare will apply in these areas.
• AT Hop adult fares for one-four stages will increase by 10c.
• Adult cash fares for three stages will increase by 50c to $5.50.
• The cost of a two-zone monthly pass will rise from $190 to $200.
• The fare between Orakei and Britomart will become a two-stage fare to align with bus fares.
• Child City Monthly Pass will increase from $80 to $90.
• Child All Zones Monthly Pass will increase from $110 to $130.
• Child Regional Monthly Pass increases from $160 to $170.