Auckland Council transport chairman Mike Lee said last month that train staff had told him people were abusing the new system when travelling between non-gated stations by carrying discount-price Hop cards but failing to tag on before boarding trains, meaning they were getting away without paying.
"There are [on-board] electronic checkers but they are slow and cumbersome and there's not enough of them," he told fellow Auckland Transport board members at their December meeting.
There was no mention of increasing the penalty charge at the open session of that meeting, but advice of the move has since appeared on Auckland Transport's website.
"If you are travelling on Auckland trains without a valid ticket or a tagged-on AT Hop card, you will be required to pay the onboard fare of $10.30 regardless of the length of your journey," the site says.
Auckland Transport spokesman Mark Hannan says the new charge will also apply to passengers who may tag on at stations but fail to tag off after completing their journeys.
He confirmed the increase but said the penalty would remain well below A$207 ($260) imposed on fare evaders in Australia.
Mr Lee said he was concerned about imposing an extra charge against those forgetting to tag off at their journeys' end.
His preference would be for gates to be installed at other stations, which Mr Hannan said would be considered in a report Auckland Transport is preparing on fare evasion.
Campaign for Better Transport convener Cameron Pitches said the new penalty seemed "a bit harsh" for passengers forgetting to tag off after short trips and wondered when Auckland Transport would offer credits to those inconvenienced by late-running trains.