A full day riding Melbourne's trains, trams and buses will cost more than $8 in 2017 when the fares go up by 5 per cent from New Year's Day.

And a two-hour trip in zone 1 will cost more than $4 for the first time, jumping by 20 cents.

News of the forthcoming rise in public transport fares comes a day after it was revealed that Victorian energy bills could balloon by as much as 10 per cent next year.