An international drug ring has been smashed after police uncovered large quantities of cocaine, methamphetamine and nearly $500,000 during raids on homes across the North Island yesterday.

The joint investigation between New Zealand Police and New Zealand Customs Service seized a quantity of meth hidden in a picture of the Virgin Mary and another stash discovered in a steel plate compactor.

Police said they seized 435 grams of methamphetamine, approximately $455,000, and clan lab-related items after searches of 112 homes in the Waikato and Wellington yesterday, as part of Operation Bali.

National Organised Crime Group director Detective Superintendent Greg Williams said Operation Bali which targeted the importation, sale and supply of cocaine and methamphetamine.

He said it began after a series of seizures at the border by Customs officers.

Ten people have been arrested and will appear in the Wellington District Court today on a range of charges, including importing Class A controlled drugs, possession for supply of Class A controlled drugs, and supplying Class A drug.

Seven men and three women, aged between 24 and 57 years, were arrested in the operation.

"[Organised crime] groups are intent on pumping as much illicit drugs as they can into our communities, causing considerable social harm, crime and victimisation," said Williams.

"Customs and Police are constantly looking to disrupt how these groups operate and we will continue to target these groups and the individuals that align themselves with them.

"This should serve as a warning to criminals everywhere who are attempting to bring drugs into New Zealand that they will be detected and they will be held accountable."

Police discovered meth hidden in a steel plate compactor. Photo / NZ Police

Customs' group manager of intelligence, investigations and enforcement, Dana McDonald, said the operation followed a series of linked seizures at the border by Customs staff, whose vigilance and diligence have paid dividends with the arrests.

"By combining our intelligence with police, we were able to uncover a wider ring of opportunist drug smugglers and dismantle their attempts to exploit our communities for a profit," he said.

Anyone with concerns or information about suspected drug dealing in their community should contact 105, or Crime Stoppers anonymously via 0800 555 111, he said.