Some Translink bus and rail fares are to go up from next Monday.
Passengers paying with cash face average rises of 2.5% on both Metro and Ulsterbus services, and a 4% increase on Northern Ireland Railway fares.
There will be no increase in the cost of Smartlink and iLink multi-journey tickets.
Translink said that it had been working hard to keep fares as low as possible but the Consumer Council said it was the "wrong time" to increase prices.
Most cash bus fares will rise by 10p but there will be no increase in the cost of the Enterprise service between Belfast and Dublin.
Translink spokesperson Ciaran Rogan said that customers should use Smartlink cards, which would save customers up to 35% compared to cash fares.
Currently 20% of Metro users and 6% of Ulsterbus customers use a Smartlink card.
Mr Rogan added: "Our bus and train services are used by almost 80 million passengers each year and recent surveys tell us that customer satisfaction remains high.
"We are confident that bus and rail travel is the most attractive and cost effective travel choice, particularly with the sharply increasing prices at the petrol pump."
The chief executive of the Consumer Council Antoinette McKeown said that passenger numbers had fallen across Translink services.
"Higher fares are not going to get people back onto the bus or train," Ms McKeown said, adding that a typical motorist was now paying £183 more a year for petrol and £204 more for diesel.
"The Consumer Council feels that Translink has missed an opportunity to encourage new passengers onto public transport by holding fares and providing a value for money alternative to the car."
SDLP regional development spokesperson Conall McDevitt said that the rises in fares was evidence that the department's public transport strategy was "failing".
He said: "DRD is obsessed with road building at the expense of sustainable transport alternatives. It's no surprise that road usage is up 17% and that private car journeys are increasing exponentially.
"Putting up public transport fares sends all the wrong messages and will be a further disincentive to switch from car to bus or rail."