Snapper chief executive Miki Szikzai said that with any new system there were changes but he was confident Aucklanders would make the adjustment.
But new Auckland customers are crying foul, registering 399 complaints with the Auckland Council's public transport provider Auckland Transport.
Those who forget to tag off are charged the highest possible fare. Others have been charged twice for one journey, only to be told by the driver there's nothing he can do.
Westmere graphic designer Honor Lock forgot to tag off and was charged about $5 on top of her usual fare.
"It is a problem remembering to tag on and off and you get a whole lot of fines.
"I was pretty pissed off and I was going to look into seeing why that was but haven't got round to it."
Another bus user, who asked not to be named, said she was charged twice for one fare on Tuesday this week.
"I tagged off and I was charged two times for a one-stage journey.
"I checked with the bus driver and he said there was nothing he could do about it."
She contacted provider NZBus the same day and was told she would have a response within a day. Three days later and after inquiries by the Herald on Sunday, NZBus apologised and offered two free rides.
Some users were fans - graphic designer Louise O'Brien was pleased with the system.
"It's good that it's electronic now. I'm sure that it speeds up the journey. It's good overall," said the 32-year-old.
NZBus did not respond before press time and Auckland Transport's Hop programme director Greg Ellis was not available for comment.
Auckland Transport communications manager Sharon Hunter said the first time people forgot to tag off they weren't charged. Any repeats, they were charged the maximum fare to prevent people cheating.
She said if people genuinely forgot to tag off, they could call Auckland Transport and plead their case. In an email she added that less than 0.1 per cent of users have had problems with tagging off.
Student Ryan Harris said this system made it easier to get ripped off. "I find it's really easy to forget. It's a natural thing to forget to tag off. I've only been using it for a week and a half and I forgot to tag off."
Auckland Council's transport committee chairman Mike Lee said the issues were "disappointing", but he had had no problems using the system.
Have you had a problem with Hop card?
Email kieran.nash@hos.co.nz