Four Singaporeans were among 41 people detained in New Zealand on drug charges during a police operation to bust a drug ring centred in the nation's North Island, the police said on Wednesday (April 13).

The four were charged after the importation of 700g of methamphetamine that was to be dealt in the city of Gisborne and its surrounding region along the east coast of the island, said a statement posted on the website of the New Zealand police.

The 41 people arrested appeared in court over the last nine days, according to the statement, and they are facing a total of 245 charges of importing a Class-A drug, conspiracy to sell, selling and possession of methamphetamine for supply and cannabis dealing.

In the operation conducted last week, which came after an eight-month investigation, the police also searched 37 properties in the Gisborne area and seized eight of them, as well as several bank accounts, vehicles, 400g of methamphetamine, firearms, cash and cannabis.

The value of the properties seized amounted to NZ$3.8 million (S$3.5 million).

Detective Sergeant Kevin Ford was quoted by the police as saying that children were living at some of the properties that were searched.

"This is a serious problem not just for police, but for the local community as a whole. These children were of various ages and had been living in houses where the drug was being used and dealt," the police quoted Sgt Ford as saying.

"The community needs to take responsibility for keeping our children safe and part of that means not exposing them to dangerous drugs and the ensuing criminal activity... This is an appalling situation."