A shake-up in how on-street parking is charged in Northern Ireland has been hit with "teething problems" which has seen people wrongly fined and charged.
In one incident it was reported a driver was wrongly charged £90 for a short parking stay.
Earlier this month the Department for Infrastructure dropped the ParkMobile application for JustPark to allow people to pay for on-street parking in Belfast, Lisburn and Newry on their mobile phones.
The change will see users pay less for transaction charges from 15p to 8p.
It's thought fewer than 25 people have been either wrongly fined for not paying for parking, when they did, or overcharged.
Some claimed they were unable to cancel bookings or received error messages that they had started a parking event and therefore unable to start another one.
JustPark blamed "teething problems" and the Department for Infrastructure apologised.
Infrastructure Minister Nichola Mallon said the penalty notices issued in error would be cancelled by Monday.
"This is another inconvenience for members of the public," she told the BBC.
"We need to make sure things like this don't happen again.
"If we are encouraging people to go on to apps and online then we need to make sure we have the infrastructure there so those errors don't occur."
The department's three-day notice of the change in provider was criticised when it was announced at the beginning of the month. However, it said ParkMobile users were sent messages and there was a two-week bedding in period before JustPark became the only application in use.
ParkMobile has been used as cashless parking system provider since it was first introduced in 2012.
Director of the Northern Ireland Retail Consortium Aodhan Connolly said it was vital people parking in towns or cities could do so with minimum hassle.