Eftpos New Zealand says retailers all over the country would still be experiencing problems with their terminals overnight.
Since yesterday, the system has been unstable, and hundreds of businesses are struggling to process payments.
Eftpos New Zealand said technicians will be working overnight on the problem.
A spokesperson said retailers should not be worried about losing money, as the transactions would be coming through once the issue is solved.
The terminal black-out should be fixed by tomorrow morning.