Commuters using Southeastern services can expect a rise in fare prices from Sunday as the franchise changes its prices for the first time in three years.
Fares on some off peak travels will go up by 3.4 per cent, or 10p, whatever is greater.
The increase comes two days before a consultation on the future of the franchise is scheduled to end.
A spokesman for Southeastern said: “We understand no one wants to pay more for their journey, which is why we’ve frozen some of our fares for the past three years. But like any business, we sometimes need to adjust our prices. When this happens we always try to keep any increases to a minimum.
“This does not affect anyone with a Season Ticket or passengers travelling in peak hours, who won’t pay any extra for their train.
“For others, we have a range of discounts including ‘advanced fares’, still at January 2016 prices, ‘GroupSave’ and our ‘Kids For A Quid’ offer. We’ve also made our cheapest online deals more widely available for our passengers, who can now buy them at their local ticket office.
“If any of our passengers want advice on how to buy their train ticket at the best possible price, our station employees are happy to help as are our Customer Services and Twitter teams. And we remain fully focused on delivering improvements across our network, to make the services we offer our passengers better.”
In proposals put forward by the Department for Transport Southeastern services on the Bexleyheath, Dartford and Greenwich lines would only go to Cannon Street.
About 640,000 journeys are made on 1,900 Southeastern trains every weekday.
Campaigners have criticized the plans to hike the fares up and urged commuters to respond to the consultation.
Lianna Etkind, public transport campaigner at Campaign for Better Transport, said: "Sneaking through fares hikes without an official announcement is an appallingly highhanded way to treat passengers.
“It's bad enough that Southeastern passengers have had to put up with years of peak fare rises while wages stagnate, but more back-door fare increases are unacceptable.
“We're urging passengers to respond to the current South Eastern franchise consultation and tell the Government that enough is enough, and passengers deserve proper value for money on their journeys."