Nearly $700,000 in total was taken via ATM machines in Canada from the accounts of about 700 New Zealanders in the scam.
According to the police summary of facts, when Chea arrived in New Zealand on Wednesday, March 14 last year he was searched by Customs officers and found in possession of items used to make the skimming devices.
Chea told the officers the items belonged to a friend and was allowed to enter the country with them.
Rivera entered the country the following day and was processed without incident.
Then on Friday, March 16, Flores Roldan and Rivera-Rivas arrived from Canada.
Flores Roldan told a Customs officer he and Rivera-Rivas were travelling together, and were in the country for a 20-day stay in the Wellington area.
During a search of Rivera-Rivas' luggage, Customs located electronic equipment concealed inside a sock.
It was seized and the pair were allowed to enter the country.
Crown prosecutor Mark Williams told the court the group came to New Zealand to carry out large scale fraud on the country's banking system.
At least $676,000 was taken from the victims' accounts.
Mr Bagley said the true dollar amount of the group's offending may never be known.
The group stole a total of 27 eftpos keypads valued at $621 each from 22 stores in Auckland and one in Hamilton between March and April last year.
The stolen keypads were opened by the offenders and electronic circuits were added.
Sleight of hand was used to unplug one keypad at a time and replace it with an identical tampered device.
The stolen keypad would then be also altered and swapped.
The modifications allowed the offenders to gain customers electronic data and access to their funds.
Those details were then sent overseas where they were used to make cloned cards for withdrawals in Montreal.
Customs said today that laws were changed in April last year to allow staff to confiscate goods believed to be used to commit crime involving dishonesty.
Before then, Customs had no legal basis to confiscate Chea's equipment. In the case of Flores Roldan and Rivera-Rivas, Customs was able to take their equipment because it had been concealed. Customs then notified police and a joint investigation was launched.
Police Financial Crime Unit Detective Sergeant Russell Bagley said outside court the operation to catch the scammers was a collaboration between police, Customs, the financial sector and the retail industry.
Within two to three weeks of the group arriving, police became aware they were involved in a sophisticated skimming operation, he said.
Mr Bagley said the legislation change now allowed Customs to seize material "much more easily''.
Although the offenders were allowed into the country after Customs discovered the equipment, Customs may not have been aware at the time what the devices were, he said.