Increased fuel costs, Government cuts, falling passenger numbers and CIE's lack of funds are all being blamed for the increases, which are set to be announced by the National Transport Authority (NTA).
The hikes will hit single and return fares paid both by cash and Leap card on Dublin Bus, Bus Eireann, Irish Rail and Luas services. Increases are expected to vary widely, with some rising by 10pc, while others will only rise by between 4-6pc and rounded up to the nearest 5c or 10c.
The increases are expected to be broadly in line with hikes of up to 10pc in monthly and annual tickets, approved in September and taking effect from January 1.
But the increase in cash single and return tickets start on December 1.
There is no single across-the-board increase, with the hikes depending on factors such as the number of stops and zones travelled, the time of travel, and passenger demand on certain routes.
The increases are expected to mean more commuters will opt for Leap cards because the gap will widen between the cheaper smart card and the dearer cash fares. CIE is being forced to hit commuters with fare increases due to a deepening cash crisis.
The current system for intercity trains is complex, with different fares for different regions and different days. While a number of fares actually fell, most increased and a handful remained the same.
Last February, the NTA also approved an application to increase prices on Dublin Bus pre-paid tickets by an average of 5.6pc.
A 30-day Rambler student card increased by nearly 5pc from €82 to €86. As well as fare hikes there are also fears about cuts in bus and rail services.
There is speculation that routes with very low usage will be either scrapped or have a reduced volume of services in a bid to stem the spiralling CIE debt.
Iarnrod Eireann expects to continue to post losses for another three years.
The company's report says it lost €20.9m last year. Bus Eireann made a small profit last year, while Dublin Bus lost €18m.